Wednesday, June 29, 2011

Digital Led Chaser circuit diagram

Digital Led Chaser circuit diagramDigital Led Chaser circuit diagram

This particular circuit employs electronic digital circuits say for example a demultiplexer and also a binary table to build designs of "moving" led lights. This simple circuit is actually awesome while employed in the dark or light up an indicator of a few type, because it produces a awesome design which attracts the eyesight.

The primary component of the circuit is a demultiplexer 74ls138, we can be connected minimally important bits on the output on the counter, which will pick out one of many pins of the demultiplexer as being the output, lighting effects the led connected to the item. The counter can be wired only to be counted, plus a time clock beat is necessary to do that operate (the time clock circuit isn't involved, but almost any can do, if it is not very noisy)

One variation to apply is to connect the most major bit of that counter to a different a line leds, allowing and also disabling one of these so the design could observe 16 leds instead of the only 8 established these.

Varying Brightness AC Lamp

Varying Brightness AC LampVarying Brightness AC Lamp

In this circuit, the SCR is required to be able to slowly range the intensity of an 120 volt lamp through managing plenty of time which the AC line voltage will be applied to the light while in every half cycle.

This circuit can be straight connected to the AC power line and also needs to be inserted inside of a enclosure which will reduce direct contact with every of the parts. To prevent electric shock, never touching every component to the circuit while it is connected to the AC power line. A 2K, 10 watt electric power resistor is required to fall the line voltage as a result of 9 volts DC. This resistor could desolve related to 7 watts and also requirements a few ventilation.

A couple of NPN transistors are employed to identify the start of each one half cycle and trigger the delay timer which often triggers the SCR by the end of the delay time. The delay time is set up by the current supply which can be controlled by a 4017 decade counter. The 1st be counted (pin 3) packages the current into a minimal that refers to about 7 milliseconds of delay, as well as almost all half cycle time so that the lamp is nearly off. Complete brightness is purchased to the sixth count (pin 1) which can be not connected so the current shall be highest and offer a minimum delay plus trigger the SCR close to the beginning of the cycle. The remaining 8 counts increment the brightness 4 steps up and 4 steps down in between highest and also minimal. Every step up or down supplies about twice or half the energy, so the intensity shows up to modify linearly. The brightness of every stage could be modified with all the 4 resistors (4. 3K, 4. 7K, 5. 6K, 7. 5K) connected on the counter outputs.

This circuit has become designed through Don Warkentien (WODEW) which suggsted introducing a tiny 47uF capacitor through ground to the junction on the current supply transistor (PNP) to relieve the a digital treading impact and so the lamp can lighten up and fade in a smoother style. The value of the capacitor depends on the 4017 counting rate, a quicker charge could need a small capacitor.

Tuesday, June 28, 2011

120V AC Line Powered LED

120V AC Line Powered LED

The following circuit diagram shows you about how to powering a LED (or two) from the 120 volt AC line applying | working with a capacitor to drop the voltage together with a little resistor to limit the inrush electric current. Considering that the capacitor need to pass current in both directions, a modest diode is connected in parallel using the LED to supply a path for the negative half cycle and also to limit the reverse voltage across the LED. A second LED using the polarity reversed could be subsituted for the diode, or perhaps a tri-color LED might be put to use which would appear orange with alternating current. The circuit is fairly efficient and draws only about a half watt from the line. The resistor value (1K / half watt) was chosen to limit the worst case inrush electric current to about 150 mA which will drop to much less than 30 mA in a millisecond as the capacitor charges. This appears to be a secure value, I've switched the circuit on and off several times without having harm to the LED. The 0.47 uF capacitor has a reactance of 5600 ohms at 60 cycles so the LED current is about 20 mA half wave, or 10 mA average. A bigger capacitor will boost the electric current along with a smaller 1 will lessen it. The capacitor should be a non-polarized kind having a voltage rating of 200 volts or a lot more.

The lower circuit is an demonstration of obtaining a low regulated voltage from the AC line. The zener diode serves as a regulator and also supplies a path for the negative half cycle electric current when it conducts inside the forward direction. In this example the output voltage is about 5 volts and will give over 30 milliamps with about 300 millivolts of ripple. Use caution when operating any electronic circuits hooked up straight to the AC line.

120V AC Line Powered LED circuit source:

Simple Door Alarm circuit

Simple Door Alarm circuitSimple Door Alarm circuit

This is a simple - easy to build - alarm circuit. For power - I used a small 9-volt battery. But the circuit itself will work from 5 to 15-volts - just choose a buzzer that's suitable for the voltage you're using. The standby current is virtually zero - so the battery life is good.

If SW1 is fitted to a door - every time the door opens the Buzzer will give a short beep. In an unattended shop - or reception area - the sound of the beep will alert you to the fact that you have a customer. How long the output lasts depends on the values of R2 and C2. With the values shown - it will last for somewhere between 3 and 5 seconds.

But - by increasing these values - you can achieve an output time of up to half-an-hour or more. So if you replace the Buzzer with a relay - and use the relay to switch a Siren - you have a Simple Intruder Alarm that you can fit almost anywhere.

I've drawn SW1 as a magnetic-reed switch; but you can use any type of switch that suits your application. If you have more than one door or window to protect - you can use more than one switch. Just wire all of your switches in series.

Changing the Output Time

Generally speaking - the length of the output time is proportional to the values of R2 and C2. In other words, if you double the value of either R2 or C2 - you will double the output time. If you halve the value of either R2 or C2 - you will halve the output time.

For example, if you replace R2 with a 4M7 resistor you will increase the output time by a factor of about 5. If you replace C2 with a 470uF capacitor you will increase the output time by a factor of about 100. If you use both a 4M7 resistor and a 470uF capacitor together, you will increase the time by a factor of about 5 X 100 = 500. This should give you an output of around half-an-hour or more.

If you want an accurate output time - use a variable-resistor (or preset) in place of R2. Then simply adjust the resistor until you get the output time you require.

Via :

A 4-Digit Keypad Controller Switch Circuit

A 4-Digit Keypad Controller Switch CircuitA 4-Digit Keypad Controller Switch Circuit

This is a universal version of the Four-Digit Alarm Keypad . I have modified the design to free up the relay contacts. This allows the circuit to operate as a general-purpose switch. It also means that it can be used to control all of my Alarm Circuits. I've used a SPCO/SPDT relay - but you can use a multi-pole relay if you wish.

The relay is energized by pressing a single key. Choose the key you want to use - and connect it to terminal "E". Choose the four keys you want to use to de-energize the relay - and connect them to "A B C & D". Wire the common to R1 and all the remaining keys to "F".

The Circuit is easy to use. When you press "E" - current through D2 & R9 turns Q6 on - and energizes the relay. The two transistors - Q5 & Q6 - form a "Complementary Latch". So - when you release the key - the relay will remain energized.

To de-energize the relay - you need to press keys "A B C & D" in the right order. When you do so - pin 10 of the IC goes high - and it turns Q4 on through R8. Q4 connects the base of Q6 to ground. This unlatches the complementary pair - and the relay drops out.

Any keys not wired to "A B C D & E" are connected to the base of Q3 by R7. Whenever one of these "Wrong" keys is pressed - Q3 takes pin 1 low and the code entry sequence fails. If "C" or "D" is pressed out of sequence - Q1 or Q2 will also take pin 1 low - with the same result. If you make a mistake while entering the code - simply start again.

The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals. The matrix type with 7 or 8 terminals will NOT do. With a 12-key pad - over 10 000 different codes are available. If you need a more secure code - use a bigger keypad with more "Wrong" keys wired to "F". A 16-key pad gives over 40 000 different codes.

Monday, June 27, 2011

12 Volt Toilet Tank Refiller circuit

12 Volt Toilet Tank Refiller circuit12 Volt Toilet Tank Refiller circuit

A bloom toilet is article that best burghal citizenry booty for granted, but it can be a affluence for those who alive far abroad from account baptize and electricity. This circuit controls a small 12 Volt pump that is acclimated to ample a toilet catchbasin from an externa rainwater accumulating cistern. Automotive windshield wiper pumps assignment accurately in this application. The 12 Volt ability in my appliance comes from a small solar ability system, it may additionally be provided by a acceptable wall-wart DC ability supply. The cistern located below the toilet tank, the pump moves the water up to the toilet's tank. The pump is switched on back the toilet catchbasin is empty, it is switched off back the catchbasin has filled.


Nominal operating voltage: 12V
Idle current: < 1 ma
Pump Current: < 5A

Sunday, June 26, 2011

14W Audio Amplifier Circuit

This Amplifier circuit designed by Mike Ellis at 1999. The amplifier capable to deliver up to 14W power audio output. The pre-amp circuit already designed in the circuit and direct connected to the amplifier modul.

Here the 14W Audio Amplifier schematic diagram:

14W Audio Amplifier Circuit diagram

For detailed explanation about this 14W amplifier circuit, visit the following page:

Led Sound Pressure Decibel Meter

Led Sound Pressure Decibel MeterLed Sound Pressure Decibel Meter

The circuit responds to sound pressure levels from about 60 to 70 dB The complete is best up by an 8 ohm speaker, amplified by a transistor date and one LM324 op-amp section. You can additionally use a activating microphone but I begin the apostle was added sensitive. The actual 3 sections of the LM324 cloister op-amp are acclimated as voltage comparators and drive 3 indicator LEDs or incandescents which are spaced about 3dB apart. An added transistor is bare for beaming lights as apparent with the lower lamp. I acclimated 12 volt, 50mA lamps. Each ablaze represents about a 3dB change in complete akin so that back all 3 lights are on, the complete akin is about 4 times greater than the akin bare to ablaze one lamp. The acuteness can be adapted with the 500K pot so that one lamp comes on with a advertence complete level. The added two lamps will again announce about a 2X and 4X access in volume.

In operation, with no input, the DC voltage at pins 1,2 and 3 of the op-amp will be about 4 volts, and the voltage on the (+) inputs to the 3 comparators (pins 5,10,12) will be about a bisected volt beneath due to the 1N914 diode drop. The voltage on the (-) comparator inputs will be about 5.1 and 6.5 which is set by the 560 and 750 ohm resistors.

When an audio arresting is present, the 10uF capacitor affiliated to the diode will allegation against the aiguille audio akin at the op-amp achievement at pin 1. As the aggregate increases, the DC voltage on the capacitor and additionally (+) comparator inputs will access and the lamp will about-face on back the (+) ascribe goes aloft the (-) input. As the aggregate decreases, the capacitor discharges through the alongside 100K resistor and the lamps go out. You can change the acknowledgment time with a beyond or abate capacitor.

This circuit requires a able-bodied filtered ability source, it will acknowledge to actual baby changes in accumulation voltage, so you apparently will charge a ample clarify capacitor affiliated anon to the 330 ohm resistor. I managed to get it to assignment with an able bank agent ability source, but I had to use 4700uF. It formed able-bodied on a adapted accumulation with alone 1000uF.


Friday, June 24, 2011

12 Volt Automatic Lamp Fader

12 Volt Automatic Lamp Fader12 Volt Automatic Lamp Fader12 Volt Automatic Lamp Fader

This circuit is agnate to the "Fading Red Eyes" ambit (in the LED section) acclimated to achromatize a brace of red LEDs. In this version, the lamps are achromatic by capricious the assignment aeon so that college ability beaming lamps can be acclimated after abundant ability loss. The switching waveform is generated by comparing two beeline ramps of altered frequencies. The college abundance access waveform (about 75 Hz.) is produced from one area of the LM324 cloister op-amp active as a Schmitt activate oscillator. The lower abundance access controls the crumbling amount and is generated from the high two op-amps agnate to the "fading eyes" circuit.

The two access waveforms at pins 9 and 1 are compared by the 4th op-amp which generates a capricious assignment aeon ellipsoidal waveform to drive the achievement transistor. A additional transistor is acclimated to alter the waveform so that one accumulation of lamps will achromatize as the added accumulation brightens. The 2N3053 will handle up to 500 milliamps so you could affix 12 strings of 4 LEDs anniversary (48 LEDs) with a 220 ohm resistor in alternation with anniversary accumulation of 4 LEDs. This would absolute about 250 milliamps. Or you can use three 4 volt, 200 mA Xmas timberline bulbs in series. For college ability 12 volt auto lamps, the transistor will charge to be replaced with a MOSFET that can handle several amps of current. See the cartoon beneath the schematic for accessible hookups.

Thursday, June 23, 2011

Relay Circuit Electronic Thermostat

Relay Circuit Electronic ThermostatRelay Circuit Electronic Thermostat

Here is a simple thermostat circuit that can be acclimated to ascendancy a broadcast and accumulation ability to a baby amplitude boiler through the broadcast contacts. The broadcast contacts should be rated aloft the accepted requirements for the heater.

Temperature changes are detected by a (1.7K @ 70F) thermistor placed in alternation with a 5K potentiometer which produces about 50 millivolts per amount F at the ascribe of the LM339 voltage comparator. The two 1K resistors affiliated to pin 7 set the advertence voltage at bisected the accumulation voltage and the hysteresis ambit to about 3 degrees or 150 millivolts. The hysteresis ambit (temperature ambit area the broadcast engages and disengages) can be adapted with the 10K resistor amid pins 1 and 7. A college amount will attenuated the range.

In operation, the alternation resistor is adapted so that the broadcast aloof toggles off at the adapted temperature. A three amount bead in temperature should account the broadcast to toggle aback on and abide on until the temperature afresh rises to the preset level. The broadcast activity can be antipodal so it toggles off at the lower end of the ambit by abandoning the locations of the 5K potentiometer and thermistor. The 5.1 volt zener diode regulates the ambit voltage so that baby changes in the 12 volt accumulation will not aftereffect operation. The voltage beyond the thermistor should be bisected the accumulation or about 2.6 volts back the temperature is aural the 3 amount ambit set by the potentiometer. Most any thermistor can be used, but the attrition should be aloft 1K ohm at the temperature of interest. The alternation resistor called should be about alert the attrition of the thermistor so the acclimation ends up abreast the centermost of the control.


Wednesday, June 22, 2011

Video Amplifier Circuit based LH0032

The following is the schematic diagram of Video Amplifier circuit, built based on LH0032, a high speed op-amp applications.

Video Amplifier circuit based LH0032

Video Amplifier Parts List:
R1 = 15Kohm+15Kohm
R2,R3,R4 = 10Kohm
R5,R6,R7,R8,R9 = 1Kohm
R10 = 820ohm
R11 = 1Mohm
R12 = 100ohm trimmer
R13,R15 = 47ohm
R14 = 10Kohm
C1 = 10uF 63V MKT
C2,C4 = 100nF 63V
C3 = 4.7pF ceramic
IC1 = LH0032
S1 = 1X2 mini switch
S2 = 1X6 sel.
J1,J2 = BNC connector

The LH0032 are very high speed general purpose operational amplifiers exhibiting 70 MHz bandwidths, 500 V/μs slew rates and 100 to 300 ns settling time to 0.1%. The LH0032 has the added advantage of FET input characteristics.

Sound Navigation Parking Assistant

Sound Navigation Parking AssistantSound Navigation Parking Assistant

The basic theory behind the Parking Assistant is the Sound Navigation and Ranging (SONAR) address that is acclimated for award the ambit and administration of a alien article underwater by transmitting complete after-effects and audition reflections from it. First, a alternation of abbreviate accelerated pulses are transmitted application a transducer that changes voltage into complete waves.

The transmitted beating is reflected off an object, and the reflected beachcomber is again accustomed by addition transducer that converts complete after-effects into voltage. The transmitted arresting is additionally accepted as the ‘ping’ and the accustomed arresting is accepted as the ‘pong’. By counting the delayed time amid the ping and the pong, the ambit amid the accessory and an article can be calmly affected by adding the delayed time with the acceleration of sound.

FM Receiver / TV Tuner TDA7000

FM Receiver / TV Tuner  TDA7000FM Receiver / TV Tuner TDA7000

This simple one chip FM receiver / TV tuner will acquiesce you to accept frequencies from 70 up to 120MHz. With this baby receiver it is accessible to auto TV stations, absolute 88 - 108MHz FM band, aircraft chat and abounding added clandestine transmissions. It is a absolute accompaniment to any FM Transmitter abnormally if FM bandage in your breadth is actual crowded. TDA7000 receiver offers actual acceptable acuteness accordingly it will alike acquiesce you to auto weaker signals that cannot be heard on accepted FM receivers.

A accurate affection of presented TDA7000 FM receiver is a voltage controlled oscillator agnate to TV tuners that are acclimated in television sets. Abundance is acquainted by capricious the ascribe voltage to the oscillator. The advantage of this blazon of oscillator is that you can use approved 100K potentiometer to absolutely tune to a accustomed broadcast. Tuning can be performed abundant quicker and absolutely than by application a trimmer (variable capacitor). Trimmers will additionally about-face the abundance as you blow them area potentiometer will not. Trimmer additionally needs to be placed on receiver's PCB to abbreviate the devious capacitance area potentiometer can be calmly placed anywhere you appetite because it will not be afflicted by any alien capacitance.


Tuesday, June 21, 2011

Brightness Control Lamps Circuit

Brightness Control Lamps Circuit
This circuit is called the Brightness Control Lamps, which assignment to ascendancy the ablaze acuteness from the four-filament lamp (ie, the arena illuminator) is accurate by two AA or AAA batteries, for close-up pictures with a agenda camera. Of advance it can be acclimated in added ways.

IC1, in principle, aftermath a 150Hz aboveboard beachcomber of capricious duty-cycle. Back the cursor from P1 is absolutely played adjoin D1, the achievement pulses arise on the absolute pin 3 of IC1 is actual narrow. Ball LP1, apprenticed by Q1, is angry off in the advance as the voltage is too low. Back the cursor is played from P1 to R2, the achievement pulses access in width, they ability the best amplitude back the potentiometer is rotated absolutely clockwise. In this way the ball alcove abounding brightness.

Part List

P1 = 470K   Linear Potentiometer
R1 = 10K
R2 = 47K
R3 = 1K5
C1 = 22nF
C2 = 100µF 25V
D1,D2 = 1N4148
IC1 = 7555 or TS555CN
Q1 = BD681
LP1 = 1.5V 200mA Bulb
SW1 = SPST Switch
B1 = 3V Batteray

Power Supply DC variable

Power Supply DC variable

This circuit is called a Power Supply DC variable is one of the best advantageous apparatus in the cyberbanking hobbyist’s work. This ambit is not an complete novelty, but a simple, reliable, “rugged” and short-proof, with a capricious voltage up to 24V and capricious so that it is up to 2A.

Capacitor C1 can be 2200 to 6800?F, 35 to 50V. For Q4 charge be army on heatsinks to accumulate a acceptable breeze of acceptable output. For the 2N3055 transistor (Q4) can be replaced with a hardly beneath able TIP3055 type.

Componen used:

P1 = 500R Linear Potentiometer

P2 = 10K Log. Potentiometer

R1, R2 = 2K2 1/2W

R3 = 330R 1/4W

R4 = 150R 1/4W

R5 = 1R 5W

C1 = 3300?F 35V

C2 = 1?F 63V

D1, D2 = 1N5402 3A

D3 = 5mm. Red LED

Q1 = BC182

Q2 = BD139

Q3 = BC212

Q4 = 2N3055

T1 = 220V Primary, 36V Center-tapped Secondary


Monday, June 20, 2011

Fm Narrow Band Transmitter 27MHz

Fm Narrow Band Transmitter 27MHz
NBFM or Attenuated Bandage Frequncy Modulation is acclimated in this 27 MHz fm transmitter circuit schematic. This circuit is an appliance by Motorola MC2833 – VHF transmitter with FM accentuation and attenuated bandage in a distinct chip. The achievement ability is 10mW (+10 dBm) and the advantage is 10 – 20m.

P1 is acclimated to acclimatize microphone addition and P2 to acclimatize the deviation. Remember that this 27MHz fm transmitter use NBFM with best 5KHz deviation, this beggarly you accept to use an nbfm receiver to access abundant audio level.

The transmitter is accessible to adjust: trim C9, C9 and C18 for best achievement ability on a bogus 50Ω load. Then accept on a 27MHz radio receiver and acclimatize P1 and P2 untill you access the best modulation. X1 = 27.005 MHz quartz


Sunday, June 19, 2011

Fading LEDs Circuit

The following diagram is the schematic diagram of fading LEDs circuit. This kind of circuit runs two LED strips in pulsing mode, i.e. one LED strip goes from off state, lights up gradually, then dims little by little, and so on. while one other LED strip does the contrary.

Fading LEDs Circuit diagram

Components part:

R1, R2 = 4K7
R3 = 22K
R4 = 1M *
R5 = 2M2 *
R6, R10, R11, R14, R15 = 10K
R7, R8 = 47K Trimpot *
R9, R13 = 27K
R12, R16 = 56R
C1 = 1µF
C2 = 100µF/25V
D1-D4 etc = 5 or 3mm LEDs *
IC1 = LM358
Q1, Q2 ,Q4 = BC327
Q3, Q5, Q6 = BC337
SW1 = SPST miniature Slider Switch
B1 = 9V PP3 Battery

Circuit Works:
The IC1 contains two Op-Amps circuit which will be used to generate triangular wave form.. The rising and falling voltage obtained at pin #7 of IC1 drives two complementary circuits formed by a 10mA continual current source (Q1, Q2 and Q5, Q6) and driver transistor (Q3 and Q6).
R4, R5 & C1 are the timing components: the total period can be varied changing their values. R7 & R8 vary the LEDs brightness.

Fading LEDs Circuit Notes:

  • For those whishing to avoid the use of trimmers, suggested values for 9V supply are: R4=3M9, R9 & R13=47K and trimmers replaced by a short.
  • Whishing to use a wall-plug adapter instead of a 9V battery, you can supply the circuit at 12V, allowing the use of up to 6 LEDs per strip, or at 15V, allowing the use of up to 7 LEDs per strip.
  • In this case, the value of the trimmers R7 & R8 should be changed to 100K.

Fading LEDs Circuit Source: RedCircuits

50W Hi Fi audio amplifier using TDA1514

50W Hi Fi audio amplifier using TDA151450W Hi Fi audio amplifier using TDA1514

The TDA1514 chip circuit is a hi-fi ability amplifier for use as a architecture block in radio, tv and added audio applications. The TDA 1514 ambit is absolutely protected, additionally has a aphasiac action that can be abiding for a aeon afterwards power-on with a adjournment time anchored by alien components. The accessory is advised for balanced ability food but an absurd accumulation may additionally be used. For stereo amplifier agreement use two identical circuits.

Audio Amplifier 8W using TDA 2030

Audio Amplifier 8W using TDA 2030
audio amplifier 8W using TDA 2030 can achievement 20 W but in this schematic we accept bargain the ability to 8w and we use 10w speakers. The ascribe sensivity is about 200mV and the amplifier is set by the 47k and 1.5k resistors.

Melody Generator using M66T

Melody Generator using M66TMelody Generator using M66T

This is the actual simple way to comedy a song with distinct 1.5 battery. You can body this circuit for allowance acceccories. When the allowance opened, again a song will be played.. It’s accessible and bargain right..? :D . It aloof use a distinct baby dent which will accomplish a song which already buried central the chip.

Components List:

C = 1uF

R = 4.7KW

Q = 2SC9013

About IC M66T series:

The M66T series is a CMOS LSI designed melody generator IC for use in telephones and toys application. It has an on-chip ROM programmed for musical performance. Produced by CMOS technology, the device results in very low power consumption. And with built-in RC oscillator, a compact melody module can be constructed with only a few additional components.

M66T pin assignment:

  • Pin 1 (O/P) Melody Output
  • Pin 2 (Vdd) Positive Power Supply
  • Pin 3 (Vss) Negative Power Supply

The following are the M66T series and the song generated by its series:

  • M66T-01L : Jingle Bells + Santa Claus Is Coming To Town + We Wish You A Merry Christmas
  • M66T-05L : Home Sweet Home
  • M66T-09L : Wedding March (Mendelssohn)
  • M66T-19L : For Alice
  • M66T-68L : It Is A Small World

16W Bridge Amplifier using LM383

16W Bridge Amplifier using LM383

The afterward diagram is 16W Bridge audio amplifier circuit. The ambit congenital based 2 pieces of ability IC LM383 in arch connection, so this amplifier is an arch amplifier.

This is an old amplifier, LM383 is discontinued, so this LM383 ability be difficult to find. You can use ECG1232, TDA2002 or TDA2003 as the alter for LM383. Take a agenda that a heatsink bowl is appropriate to abstain overheating on the ICs.


Friday, June 17, 2011

5V DC / 10A Power Supply Offline Switching

5V DC / 10A Power Supply Offline Switching5V DC / 10A Power Supply Offline Switching

Offline switching ability accumulation which consistent 5VDC/10A achievement from 110/220V AC home ability electric. See the genitalia list, there should be altered MOSFET blazon for 110V anf 220V volatage input.

The schematic shows a 50-W ability accumulation with a 5-V 10-A output. It is a flyback advocate operating central the connected mode. The ambit has functionality of a capital ancillary and accessory ancillary ambassador will full-protection from accountability altitude such as overcurrent. When the accountability action has been removed, the ability accumulation will go into the soft-start aeon aloof afore recommencing accustomed operation.


Smoke Detector using IC RE46C140

Smoke Detector using IC RE46C140Smoke Detector using IC RE46C140

Using the IC RE46C140 chip circuit you can architecture smoke detector anxiety application few alien cyberbanking components. The IC RE46C140 is a low ability CMOS photoelectric blazon smoke detector IC that will accommodate all the appropriate appearance for a photoelectric blazon smoke detector activity .

This smoke detector anxiety architecture incorporates a accretion selectable photo amplifier for use with an bittersweet emitter detector pair.

An centralized oscillator strobes ability to the smoke apprehension chip for 100us every 10 abnormal to accumulate standby accepted to a minimum. If smoke is sensed the apprehension amount is added to verify an anxiety condition.

An interconnect pin allows assorted detectors to be affiliated such that back one units alarms, all units will sound.

An centralized 10 minute timer can be acclimated for a bargain acuteness mode. In standby the LED is pulsed on for 10mS every 43 abnormal . In a bounded anxiety action or the advance to analysis anxiety the LED beating abundance is added to already every .5 seconds. In the case of a alien anxiety the LED not active. In the timer approach of operation the LED is pulsed on for 10mS every 10 seconds.

A comparator compares the photo amp achievement to an centralized advertence voltage. If the appropriate cardinal of after smoke altitude is met the accessory will go into bounded anxiety and the horn will be active.

The bidirectional IO pin allows alternation of assorted detectors. In a bounded anxiety action this pin is apprenticed aerial anon through a connected accepted source. Shorting this achievement to arena will not account boundless current. The IO is abandoned as an ascribe during a bounded alarm. This smoke detector ambit charge be powered from a 9 volt DC ability supply.


Metal Detector using 555 Timer Suite

Metal DetectorMetal Detector using 555 Timer Suite

A actual simple metal detector cyberbanking activity can be advised application a simple 555 timer chip ambit . As you can see in the schematic ambit , this cyberbanking activity requires few alien cyberbanking genitalia .

This circuit detects metal and additionally magnets. When a allurement is brought abutting to the 10mH choke, the achievement abundance changes.

This metal detector activity can be powered from a ability accumulation that can accommodate an achievement DC voltage amid 6 an 12 volt .

If a metal is afterpiece to the L1 braid , will aftermath a change of achievement cadence frequency, that will accomplish a complete in the 8 ohms speaker.


Honda Motorcycle CB750F Ciruit Diagram

Honda Motorcycle CB750F Ciruit DiagramHonda Motorcycle CB750F Ciruit Diagram

The afterward account shows the electrical base affiliation diagram for Honda Motorcycle CB750F. It shows the affiliation amid Honda genitalia such as the appropriate about-face arresting indicator light, oil burden admonishing light, aloof indicator, aerial axle indicator, about-face arresting indicator, tachometer lights, speedometer lights.

turn/signal active lights, headlight, about-face signal/running light, horn and horn button, clamp switch, advanced stop switch, about-face arresting ascendancy switch, dimmer switch, agent stop switch, atom units, aloof switch, oil burden switch, rear stop switch, fuses, agitation switch, amateur motor, battery, about-face arresting appropriate rear, appendage and anchor light, about-face arresting larboard rear, regulator/rectifier, alternator, agitation coils, beating generator, atom plugs, and additionally the blush code.

GSM Cell Phone Jammer Circuit

GSM Cell Phone Jammer CircuitGSM Cell Phone Jammer Circuit

A admirable diy gsm jammer or cellular adaptable buzz jammer schematic diagram for use alone in GSM1900 with abundance from 1930 MHz to 1990 MHz. The GSM1900 cellular corpuscle buzz arrangement is fabricated use of by USA, Canada and best of the nations in South America.

This cellular buzz jammer isn't applicative for use in Europe, Center East, nor Asia. The GSM jammer ambit could block adaptable adaptable buzz signals which operates on GSM1900 band, additionally articular as DCS.

68W Power Amplifier using LM3886

68W Power Amplifier using LM388668W Power Amplifier using LM3886

The LM3886 is a high-performance audio power amplifier capable of delivering 68W of continuous average power to a 4 load and 38W into 8 with 0.1% THD+N from 20Hz-20kHz.


Maximum Output Power : 68W RMS - 108W Peak

THD : %0.03 at 60W

SNR : 110dB at 60 W - 92.5dB at 1W

PSRR : 120dB

Protection circuitries : DC /AC Short circuit protection and thermal protection

Output Class : Conjugate AB-A

The achievement of the LM3886, utilizing its Self Peak Direct Temperature (°Ke) (SPiKe™) aegis circuitry, puts it in a chic aloft detached and amalgam amplifiers by accouterment an inherently, dynamically adequate Safe Operating Area (SOA). SPiKe aegis agency that these genitalia are absolutely safeguarded at the achievement adjoin overvoltage, undervoltage, overloads, including shorts to the supplies, thermal runaway, and direct temperature peaks.

The LM3886 maintains an accomplished signal-to-noise arrangement of greater than 92dB with a archetypal low babble attic of 2.0µV. It exhibits acutely low THD+N ethics of 0.03% at the rated achievement into the rated amount over the audio spectrum, and provides accomplished breadth with an IMD (SMPTE) archetypal appraisement of 0.004%.


Tuesday, June 14, 2011

Audio Stereo Channel Selector Circuit

Audio Stereo Channel Selector CircuitAudio Stereo Channel Selector Circuit

This circuit has accouterment for abutting stereo outputs from four altered sources/channels as inputs and alone one of them is selected/connected to the achievement at any one time.

When ability accumulation is angry ‘on’, approach A (AR and AL) is selected. If no audio is present in approach A, the ambit waits for some time and again selects the abutting approach (channel B). This chase operation continues until it detects audio arresting in one of the channels. The inter-channel adjournment or adjournment time can be adapted with the advice of preset VR1. If still best time is needed, one may alter capacitor C1 with a capacitor of college value.

Suppose approach A is affiliated to a band recorder and approach B is affiliated to a radio receiver. If initially approach A is selected, the audio from the band recorder will be present at the output. After the band is played completely, or if there is acceptable abeyance amid after recordings, the ambit automatically switches over to the achievement from the radio receiver. To manually skip over from one (selected) alive approach to addition (non-selected) alive channel, artlessly advance the skip about-face (S1) briefly already or more, until the adapted approach ascribe gets selected. The called approach (A, B, C, or D) is adumbrated by the aglow of agnate LED (LED11, LED12, LED13, or LED14 respectively).

IC CD4066 contains four alternation switches. These switches are affiliated to four abstracted channels. For stereo operation, two agnate CD4066 ICs are acclimated as apparent in the circuit. These alternation switches are controlled by IC CD4017 outputs. CD4017 is a 10-bit arena adverse IC. Since alone one of its outputs is aerial at any instant, alone one about-face will be bankrupt at a time. IC CD4017 is configured as a 4-bit arena adverse by abutting the fifth achievement Q4 (pin 10) to the displace pin. Capacitor C5 in affiliation with resistor R6 forms a power-on-reset ambit for IC2, so that on antecedent switching ‘on’ of the ability supply, achievement Q0 (pin 3) is consistently ‘high’. The alarm arresting to CD4017 is provided by IC1 (NE555) which acts as an astable multivibrator back transistor T1 is in cut- off state.

IC5 (KA2281) is acclimated actuality for not alone advertence the audio levels of the called stereo channel, but additionally for advanced biasing transistor T1. As anon as a specific beginning audio akin is detected in a called channel, pin 7 and/or pin 10 of IC5 goes ‘low’. This low akin is accompanying to the abject of transistor T1, through diode-resistor aggregate of D2-R1/D3-R22. As a result, transistor T1 conducts and causes achievement of IC1 to abide ‘low’ (disabled) as continued as the called approach achievement exceeds the preset audio beginning level.

Presets VR2 and VR3 accept been included for acclimation of alone audio beginning levels of larboard and appropriate stereo channels, as desired. Already the multivibrator activity of IC1 is disabled, achievement of IC2 does not change further. Hence, analytic through the channels continues until it receives an audio arresting beyond the preset beginning value. The skip about-face S1 is acclimated to skip a approach alike if audio is present in the called channel. The cardinal of channels can be calmly continued up to ten, by application added 4066 ICs.


High Gain Crystal Earphone Amplifier

High Gain Crystal Earphone AmplifierHigh Gain Crystal Earphone Amplifier

This simple, one-transistor amplifier provides a voltage accretion over 1000 (60 dB) for active a aerial impedance bowl (crystal) earphone. The aerial accretion is accomplished by replacing the acceptable beneficiary resistor with an abnormal constant-current diode that food 1/2 mA yet exhibits a actual aerial attrition to the audio. This amplifier will accord accomplished array life, cartoon alone 500 uA.

Below is a archetypal appliance application it with the aboriginal clear radio ambit on this page. The amplifier provides acceptable aggregate with a bashful antenna. You may appetite a aggregate ascendancy as with the TL431 project! Or use the Crystal Radio RF Amplifier directly above for even more sensitivity with less than 2 mA current drain.


Crystal Radio Audio Amplifier Circuit

Crystal Radio Audio Amplifier CircuitCrystal Radio Audio Amplifier Circuit

Here is a simple audio amplifier application a TL431 blow regulator. The amplifier will accommodate room-filling aggregate from an accustomed clear radio outfitted with a long-wire antenna and acceptable ground. The chip is agnate in complication to a simple one-transistor radio but the achievement is far superior.

The TL431 is accessible in a TO-92 amalgamation and it looks like an accustomed transistor so your hobbyist accompany will be afflicted by the aggregate you are accepting with alone one transistor! The amplifier may be acclimated for added projects, too. Higher impedance headphones and speakers may additionally be used. An earphone from an old blast will accord boisterous aggregate and abundant sensitivity! The 68 ohm resistor may be added to several hundred ohms back application aerial impedance earphones to save array power.

Phone Ring Generator Using Switching Supply

Phone Ring Generator Using Switching SupplyPhone Ring Generator Using Switching Supply Circuit

The telephone ring generator shown generates the bare aerial voltage from a simple switching approach ability accumulation (SMPS) which employs a CMOS Schmitt Trigger aboveboard beachcomber oscillator, 10 mH inductor, aerial voltage switching transistor (TIP47 or added aerial voltage, 1 amp transistor) and a disciplinarian transistor (2N3053). The inductor should accept a low DC attrition of 1.5 ohms or less. The switching accumulation charge accept a amount affiliated to anticipate the voltage from ascent too high, so a 22K resistor is acclimated beyond the achievement which banned the voltage to about 120 DC with the buzz ringer broken and about 90 volts DC connected. The achievement voltage can be adapted by alteration the amount of the 150K resistor amid pins 10 and 11 which will adapt the oscillator abundance (frequency is about 800 Hz as shown).

The accumulation is gated on and off by a additional Schmitt Trigger oscillator (pins 12/13) so that the buzz rings for about 2 abnormal and again the ambit idles for about a minute amid rings. These times can be adapted with the 10K and 300K resistors affiliated to pin 12. The advance button apparent is acclimated to manually arena the phone. The 25Hz campanology abundance is generated by addition Schmitt Trigger oscillator (pins 1/2) which controls the H arch transistor achievement circuit. The 6 transistors in the achievement date (4 NPN, 2 PNP) should be aerial voltage types rated at 200 volts beneficiary to emitter or more. The ringer will alone draw about 10 mA, so the achievement transistors can accept a low accepted appraisement but charge accept a aerial voltage rating. I acclimated TIP47s and baby arresting PNPs of alien numbers that I had on hand, but added types such as NTE287 (NPN) and NTE288 (PNP) should work. Both accept a 300 volt C-E appraisement and amount about $0.95 from mail adjustment houses.

The two 470 ohm resistors affiliated to the achievement serve to absolute the accepted in case the achievement is shorted. I never approved shorting the achievement to see how able the resistors are, but I did lose a brace transistors and again absitively to add the resistors. They should absolute the billow to about 120 mA which should be low abundant to anticipate damage. The ambit draws about 250 mA back the arena arresting is present so if you appetite to accomplish it from batteries, six 'D' blazon acrid beef are recommended. It apparently won't assignment with a baby 9 volt battery.


32.768 KHz Oscillator using Watch Crystal

32.768 KHz Oscillator using Watch Crystal32.768 KHz Oscillator using Watch Crystal

a 32.768 KHz square wave from a common watch crystal. The output can be fed to a 15 stage binary counter to obtain a 1 second square wave. The circuit on the left using the 4069 inverter is recommended over the transistor circuit and produces a better waveform. The single transistor circuit produces more of a ramping waveform but the output swings the full supply voltage range so it will easily drive the input to a CMOS binary counter.

88-108 MHz FM Transmitter Beacon Broadcast

88-108 MHz FM Transmitter Beacon Broadcast
This 88-108 MHz FM Transmitter Beacon Broadcast circuit will address a connected audio accent on the FM advertisement bandage (88-108 MHz) which could acclimated for alien ascendancy or aegis purposes. Ambit draws about 30 mA from a 6-9 volt array and can be accustomed to about 100 yards. A 555 timer is acclimated to aftermath the accent (about 600 Hz) which abundance modulates a Hartley oscillator. A added JFET transistor absorber date is acclimated to abstract the oscillator from the antenna so that the antenna position and breadth has beneath aftereffect on the frequency. Fine abundance acclimation can be fabricated by adjusting the 200 ohm resistor in alternation with the battery.

Oscillator abundance is set by a 5 about-face broke inductor and 13 pF capacitor. The inductor was anguish about a #8 X 32 bolt (about 3/16 diameter) and again removed by unscrewing the bolt. The inductor was again streached to about a 3/8 inch breadth and broke abreast the center. The oscillator abundance should appear out about abreast the centermost of the bandage (98 MHz) and can be confused college or lower by hardly accretion or burden the inductor. A baby arresting diode (1N914 or 1N4148) is acclimated as a varactor diode so that the absolute accommodation in alongside with the inductor varies hardly at the audio amount appropriately causing the oscillator abundance to change at the audio amount (600 Hz).

The ramping waveform at pins 2 and 6 of the timer is activated to the antipodal biased diode through a ample (1 Meg) resistor so that the capacitance of the diode changes as the ramping voltage changes appropriately altering the abundance of the catchbasin circuit. Alternately, an audio arresting could be activated to the 1 Meg resistor to attune the oscillator but it may crave an added pullup resistor to about-face bent the diode. The N approach JFET transistors acclimated should be aerial abundance VHF or UHF types (Radio Shack #276-2062 MPF102) or similar.

Parallel Relay Interface Port

Parallel Relay Interface PortParallel Relay Interface Port Schematic

authoritative a broadcast from the PC's alongside printer anchorage (LPT1 or LPT2). Amount A shows a solid accompaniment broadcast controlled by one of the alongside anchorage abstracts curve (D0-D7) application a 300 ohm resistor and 5 volt ability source. The solid accompaniment broadcast will animate back a "0" is accounting to the abstracts line. Amount B and C appearance automated relays controlled by two transistors. The broadcast in amount B is activated back a "1" is accounting to the abstracts band and the broadcast in amount C is activated by autograph a "0" to the line. In anniversary of the three circuits, a accepted affiliation is fabricated from the abrogating ancillary of the ability accumulation to one of the anchorage arena pins (18-25).

There are three accessible abject addresses for the alongside anchorage You may charge to try all three abject addresses to actuate the actual abode for the anchorage you are application but LPT1 is usually at Hex 0378. The QBasic "OUT" command can be acclimated to accelerate abstracts to the port. OUT, &H0378,0 sets D0-D7 low and OUT, &H378,255 sets D0-D7 high. The alongside anchorage additionally provides four ascendancy curve (C0,C1,C2,C3) that can be set aerial or low by autograph abstracts to the abject address+2 so if the abject abode is Hex 0378 again the abode of the ascendancy latch would be Hex 037A. Note that three of the ascendancy $.25 are astern so autograph a "0" to the ascendancy latch will set C0,C1,C3 aerial and C2 low.


AM Broadcast Transmitter Micro Power

AM Broadcast Transmitter Micro Power

In this AM Broadcast Transmitter Micro Power circuit, a 74HC14 hex Schmitt activate inverter is acclimated as a aboveboard beachcomber oscillator to drive a baby arresting transistor in a chic C amplifier configuration. The oscillator abundance can be either anchored by a clear or fabricated adjustable (VFO) with a capacitor/resistor combination. A 100pF capacitor is acclimated in abode of the clear for VFO operation. Amplitude accentuation is able with a additional transistor that controls the DC voltage to the achievement stage. The modulator date is biased so that bisected the accumulation voltage or 6 volts is activated to the achievement date with no modulation. The achievement date is acquainted and akin to the antenna with a accepted capricious 30-365 pF capacitor.

About 20 milliamps of accepted will breeze in the antenna advance (at frequencies abreast the top of the band) back the achievement date is optimally acquainted to the oscillator frequency. A baby 'grain of wheat' lamp is acclimated to announce antenna accepted and optimum settings. The 140 uH inductor was fabricated application a 2 inch breadth of 7/8 inch (OD) PVC aqueduct anguish with 120 turns of #28 chestnut wire. Best achievement is acquired abreast the aerial end of the advertisement bandage (1.6 MHz) back the antenna breadth is alone a actual baby atom of a wavelength. Input ability to the amplifier is beneath than 100 milliwatts and antenna breadth is 3 meters or beneath which complies with FCC rules. Achievement ability is about in the 40 microwatt ambit and the arresting can be heard about 80 feet. Radiated ability achievement can be approximated by alive out the antenna radiation attrition and adding by the antenna accepted squared. The radiation attrition for a dipole antenna beneath than 1/4 amicableness is

R = 80*[(pi)^2]*[(Length/wavelength)^2]*(a agency depending on the anatomy of the accepted distribution) The agency depending on the accepted administration turns out to be [(average accepted forth the rod)/(feed current)]^2 for abbreviate rods, which is 1/4 for a linearly-tapered accepted administration falling to aught at the ends. Even if the rods are capped with plates, this agency cannot be beyond than 1. Substituting ethics for a 9.8 bottom dipole at a abundance of 1.6 MHz we get R= 790*.000354*.25 = .07 Ohms. And the attrition will be alone bisected as abundant for a monopole or 0.035 Ohms. Radiated ability at 20 milliamps works out to about I^2 * R = 14 microwatts.


Digital Electronic Lock Schematic

Digital Electronic Lock SchematicDigital Electronic Lock Schematic

The agenda lock apparent beneath uses 4 accepted argumentation ICs to acquiesce authoritative a broadcast by entering a 4 chiffre cardinal on a keypad. The aboriginal 4 outputs from the CD4017 decade adverse (pins 3,2,4,7) are gated calm with 4 digits from a keypad so that as the keys are depressed in the actual order, the adverse will advance. As anniversary actual key is pressed, a low akin appears at the achievement of the bifold NAND aboideau bearing a aerial akin at the achievement of the 8 ascribe NAND at pin 13.

The cursory aerial akin from pin 13 activates a one attempt ambit which applies an almost 80 millisecond absolute activity beating to the alarm band (pin 14) of the decade adverse which advances it one calculation on the ascent edge. A added monostable, one attempt ambit is acclimated to accomplish an almost 40 millisecond absolute activity beating which is activated to the accepted point of the keypad so that the adapted NAND aboideau will see two argumentation aerial levels back the actual key is apprenticed (one from the adverse and the added from the key). The astern alarm beating (negative going) at pin 12 of the 74C14 and the absolute activity keypad beating at pin 6 are gated calm application two diodes as an AND aboideau (shown in lower appropriate corner). The achievement at the alliance of the diodes will be absolute in the accident a amiss key is apprenticed and will displace the counter.

Back a actual key is pressed, outputs will be present from both monostable circuits (clock and keypad) causing the displace band to abide low and acceptance the adverse to advance. However, back the keypad beating begins hardly afore the clock, a 0.1uF capacitor is affiliated to the displace band to adjournment the displace until the astern alarm arrives. The ethics are not analytical and assorted added timing schemes could be acclimated but the alarm arresting should be hardly best than the keypad beating so that the alarm arresting can affectation out the keypad and abstain resetting the adverse in the accident the alarm beating ends afore the keypad pulse. The fifth achievement of the adverse is on pin 10, so that afterwards four actual key entries acquire been made, pin 10 will move to a aerial akin and can be acclimated to actuate a relay, brighten an LED, ect. At this point, the lock can be displace artlessly by acute any key.

The circuit can be continued with added gates (one added CD4011) to acquire up to a 8 chiffre code. The 4017 counting adjustment is 3 2 4 7 10 1 5 6 9 11 so that the aboriginal 8 outputs are affiliated to the NAND gates and pin 9 would be acclimated to drive the broadcast or light. The 4 added NAND aboideau outputs would affix to the 4 actual inputs of the CD4068 (pins 9,10,11,12). The ambit will accomplish from 3 to 12 volts on 4000 alternation CMOS but alone 6 volts or beneath if 74HC genitalia are used. The ambit draws actual little accepted (about 165 microamps) so it could be powered for several months on 4 AA batteries bold alone alternate use of the relay.

3W HF QRP Linear Amplifier

3W HF QRP Linear Amplifier3W HF QRP Linear Amplifier Circuit

This is a rather abnormal QRP Ability Amplifier design, with a advanced abundance response; aural three dB's from 300KHz to 30MHz. Overall accretion is in the arena of 16dB and the final achievement ability may be able-bodied over four watts.

The advanced bandwidth is a aftereffect of the architecture of the RF transformers, T1 and T2. These are anguish on 2-hole ferrite balun cores as frequently begin in the old ancient valve TV sets (e.g. Phillips 4322-020-31520). Twist 2 lengths of 22 SWG enamelled wire calm and wind as shown. Connect the end of the "A" ambagious to the alpha of the "B" winding. Use this alliance as the centre-tap of the transformer.

This PA will bear 4 watts continuously (with a acceptable heatsink), and may be loaded into a circumlocute or accessible ambit after causing damage. This makes it about the ideal PA for outdoor/field use. Above is the abounding ambit diagram of the RFPA and the braid ambagious pattern. This PA may be acclimated for for SSB, as able-bodied as CW (and AM?).

Set RV1 to MINIMUM attrition and administer 12volt ability with NO DRIVE. Adjust RV1 for about 250mA DC absolute accumulation current. This may be be bargain to a abundant abate accepted if lower achievement admiral (reduced drive) is used.


50W Amplifier Circuit based ICL8063 + 2N3055

50W Amplifier Circuit, built based ICL8063 as power transsistor driver and 2N3055 as main power amplifier component.

50W Amplifier Circuit based ICL8063 + 2N3055 schematic diagram:
electronic circuit diagram

Parts List:
R1 = 200 Ohm
R2 = 200K
R3 = 30K
R5 = 1K
R6 = 5K
R7, R10 = 1 Meg
R8,R9 = 0.4 Ohm/5Watt
R11 = 10K Potensiometer
R12,R13 = 51K
R14 = 47K
C1 = 100uF/35V
C2 = 0.011uF
C3 = 3750pF
C4,C6 = 1000pF
C5,C7,C8 = 0.001uF
C9 = 50pF
C10 = 0.3uF
C11,C12 = 10.000uF/50V
U1,U2 = 741 Op Amp
U3 = ICL8063 Audio Amp Transister Driver
Q1 = 2N3055 NPN Power Transistor
Q2 = 2N3791 PNP Power Transistor
BR1 = 250 V 6 Amp Bridge Rectifier
T1 = 50V Center Tapped 5 Amp Transformer
S1 = SPST 3 Amp Switch
S2 = DPDT Switch
F1 = 2 Amp Fuse
SPKR1 = 8 Ohm 50W Speaker

Circuit Notes:
  • Distortion is much less than 0.1% up to 100HZ and increases to about 1% at 20kHz.
  • 50V CT transformer might be difficult to find, you may use 45V or 32V CT transformer.
  • Q1 and Q2 should be use heatsinks to prevent over heating.
50W Amplifier Circuit based ICL8063 + 2N3055 source page

Saturday, June 11, 2011

5W PLL FM transmitter circuit

5W PLL FM transmitter circuit
Here's 5W PLL FM transmitter circuit . This ambit uses the accustomed 2SC1971 for final ability amplifier stage. Click angel beneath for enlarge the ambit schematic.

The PLL controller of the FM transmitter use SAA1057 and PIC16F628 (download HEX file). If appetite to change the alive component, here's the list:

2SC2458 = BC547
2SA1048 = BC557
2SK192 = J310
2SB562 = BD136, BD138, BD140
2SC1923 = BF199 of BRF91 2SC1923 = BF199 or BRF91
2SC2053 = BRF96
2SB1135 = BD136, BD138, BD140
MV2105-09 = BB105, BB119

Printed Circuit Board (PCB) for this FM transmitter circuit is 155 mm x 120 mm. All coils are 0.8 mm copper wire with a 6 mm diameter. Please see parts used from schematic.


12KV High Voltage Generator

12KV High Voltage Generator

The 12KV High Voltage Generator beneath uses an abnormal adjustment to accomplish about 12,000 volts with about 5uA of current. Two SCRs anatomy two beating architect circuits. The two SCRs acquittal a 0.047uF a 400v capacitor through a xenon lamp activate braid at 120 times a second.

The aerial voltage pulses produced at the accessory of the activate braid are rectified application two 6KV damper diodes. The voltage doubler ambit at the accessory of the activate braid accuse up two aerial voltage disc capacitors up to about 12KV. Although this ambit can’t aftermath a lot of accepted be actual accurate with it. A 12KV atom can jump about 0.75 of an inch so the cyberbanking ambit needs to be anxiously active with lots of amplitude amid components.

circuit designed by David Johnson, P.E.


Excellent Electronics Heterodyne Detector

Excellent Electronics Heterodyne DetectorExcellent Electronics Heterodyne Detector

The bat ultrasounds are best up by the microphone SPKR1 and go through two stages of addition at Q1 and Q2. Separately, a tunable (R12) distinct abundance is produced by the LM567 oscillator U1. The LM567 is a accent decoder but actuality its ascribe is ashore and its voltage controlled oscillator is acclimated as a attention oscillator. The oscillator abundance is accustomed by

    f = 1/(1.1*C4*(R10 + R12))
= 1/(1.1*0.0022*10-6*(4.7 + [0-50])*103)
= [88-7.5] khz

The two signals are alloyed at Q3 to aftermath both a arresting in the audio ambit and college frequencies that are again filtered out.

The actual audio arresting undergoes a aftermost date of controlled (R13) addition with the LM386 at U2 afore actuality accessible for achievement at AUDIO OUT. The ability antecedent is a simple 9V battery, so this apparatus is absolutely portable.


Powerful Bat Detector device

Powerful Bat Detector devicePowerful Bat Detector device Circuit Diagram

The Powerful Bat Detector is a abundance analysis blazon device. Abundance analysis blazon detectors acquiesce you to apprehend accelerated complete by digitally ascent the abundance bottomward into the animal audition range. For instance, a western pipistrelle bat emits accelerated complete in the ambit of 53 to 91 kHz. If you bisect that abundance by 16, the new abundance ambit is 3.3 to 5.7 kHz, calmly aural our audition range. Because the analysis is done digitally, all amplitude advice is lost. Accelerated sources candy by the detector catechumen to sounds like geiger-counter clicks and chirps.

The basal ambit of the Simple Bat Detector is apparent in the schematic diagram to the right. It is about composed of 3 chip circuits, or ICs. The arresting from an accelerated transducer is fed to IC-1, an LM386 audio amplifier, which is configured to accommodate a arresting accretion of 200. The arresting is accompanying to IC-2, a added LM386, by a .05 uf capacitor. IC-2 is configured to accommodate an added accretion of 20, for a absolute arrangement accretion of 4,000. The achievement of IC-2 is absolute accompanying to the ascribe of IC-3, a 7 date CMOS agenda affiliate circuit. The ascribe date of the affiliate acts as a aught bridge detector, triggering on the abrogating alteration of the arresting from IC-2. The bisect by 16 achievement is affiliated to a potentiometer, which serves as an audio akin control. A aerial impedance bowl earphone is affiliated to the achievement of the akin control. The 10K akin ascendancy is a baby printed ambit pot that is set and forgotten. The detector ambit is powered by a nine volt battery. ( The numbers abutting to the IC nodes accredit to the pin numbers of the IC's. Note the added pins listed at the basal of the schematic that charge to be angry to ground. )

A above advantage of a abundance analysis detector is that it is a advanced bandage accessory ... that agency it will let you apprehend all apparent bat sounds after the charge to tune the detector to any accurate frequency. Heterodyne detectors, which action accelerated complete in the analog domain, alone catechumen a baby ambit of frequencies at any accustomed time - you charge baddest which frequencies to accept to. If you tune up about 60 kHz to accept for a pipistrelle, you may not apprehend the big amber bats aerial nearby. The abundance analysis detector works in the agenda domain, converting the abounding spectrum of complete that the transducer is able to detect. So you get to accept to all of the accelerated sounds about you, after missing annihilation due to adverse affability choices. I feel this no-knobs-needed appropriate of the abundance analysis detector makes it a abundant best for the accidental bat observer, and student.


Friday, June 10, 2011

LM3886: 68W Power Amplifier

This is a good amplifier circuit taken from Built based LM3886, the amplifier capable to deliver up to 68W audio output.

LM3886: 68W Power Amplifier circuit diagram

Parts List:

R1 = 10K Ohms
R2 = 10 Ohms 2W see text
R3 = 10 Ohms
R4 = 47K Ohms
R5 = 220K Ohms
R6 = 10K Ohms
R7 = 100K Ohms
L1 0,7uH
IC1 LM3886
C1 = 100NF
C2 = 100NF
C3 = 100NF
C4 = 100UF
C5 = 100UF
C6 = 4,7UF
C7 = 100UF
C8 = 1UF

The amplifier should be supplied by +34 and –34 volts. R2 and L1 is a resistor of 10 ohms / 2 watt coiled with 10 to 12 you exhale of enameled thread AWG 20.

68W Power Amplifier circuit diagram based LM3886

Thursday, June 9, 2011

Battery-backup converter with one NiCd cell

Battery-backup converter with one NiCd cellBattery-backup converter with one NiCd cell

Notebook computers and added carriageable accessories generally use a advancement array to absorb anamnesis accommodation during advancement of the capital battery. Such "bridge batteries" usually abide of bristles or six series-connected NiCd bread cells. They're accepted to accumulate the arrangement animate for about 5 minutes—plenty of time to bandy batteries. The ambit in Figure 1 reduces size, weight, and amount by application one NiCd corpuscle instead of bristles or six. A Saft VB4E 40-mAhr NiCd bread corpuscle has abundant accommodation to accumulate a archetypal anthology computer in append approach for about 10 minutes. All apparatus (excluding the bread cell) absorb beneath than 1/2 in.2 of pc-board area, and the amount accumulation from beneath beef advice pay for the added circuitry.

When it's operational, the capital array provides ability to the system's dc/dc converters. The LT1304 addition advocate consistently monitors the dc/dc-converter ascribe via the acknowledgment affiliate absolute R3 and R4. Once the FB pin drops beneath 1.24V (corresponding to about 6V at the dc/dc-converter input), addition advocate IC1 begins switching. Accepted comes from B1, through L1, and into the SW pin on IC1. When IC1's centralized about-face turns off, the SW pin goes high, carrying accepted through D2 into the dc/dc converter's ascribe capacitor, C4. C4 already exists for the dc/dc converter, so you allegation no added achievement capacitor.

The LT1304 switches at about 200 kHz; thus, L1 can be small. Switching occurs automatically as bare to authority the dc/dc converter's ascribe at about 6V. Ability for IC1 is "bootstrapped" from the 5V dc/dc converter's output, so it never needs to accomplish anon from the 1.2V NiCd bread cell. Should the advancement array anytime absolutely discharge, the 5V achievement drops beneath the LT1304's minimum operating voltage of 1.5V, and the absolute arrangement shuts down. At that point, the NiCd corpuscle becomes unloaded, thereby preventing overdischarge damage. Advancement operation is re-established alone afterwards the capital ability antecedent (main array or ac power) is adequate to the system.

It is generally all-important to accomplish a argumentation arresting to announce that the arrangement is accepting its ability from the advancement battery. This arresting can serve to afford amount (the advancement advocate cannot abutment abounding arrangement power) or to accessible a MOSFET about-face that prevents accepted from abounding aback into the capital battery. When the LT1304 is operating, the flyback beating present at the SW pin turns on Q1, thereby peak-charging C1 through D1. Once the voltage on pin 1 exceeds 1.17V (the LBI comparator threshold), the LBO open-collector disciplinarian is appear and pulled aerial by the resistors aural Q2.

You can affix the LBO arresting to argumentation chip or to a microcontroller input. LBO additionally turns off Q2 to attenuate charging during advancement operation. During accustomed nonbackup operation, LBO is low, befitting Q2 saturated. In this state, about 350 mA of charging accepted flows through R5 into the battery. You can calibration R5 for altered allegation currents as appropriate.


Microphone Preamp Low Noise Balanced

Microphone Preamp Low Noise BalancedMicrophone Preamp Low Noise Balanced Circuit Diagram

The ascribe date is configured for atomic babble and this has meant a non IC approach. There are some appropriate ICs that can be acclimated for mic pre-amps, they accommodate a ambit like this one except bogus on one chip. Examples accommodate the SSM2017 (now obsolete) or the backup INA103 or similar.

Components should all be readily accessible except for the 10 k ohm pot for the accretion control. This needs to be a about-face log abate - or abroad use a multi-position about-face with 6 dB accretion accomplish accoutrement the 60 dB ambit of the circuit. Accomplish abiding it is accomplish afore break.

Editor's Note - Alternatively, a accepted log pot can be used, but active "backwards". This will assignment accomplished if it is labelled "Attenuation" instead of "Gain". As the pot is avant-garde clockwise, the accretion is bargain (attenuation is increased). Maximum accretion will accordingly be activated back the pot is absolutely anti-clockwise. Note that this is not a botheration that is specific to this ambit - all the IC mic preamps accept absolutely the aforementioned problem.

The +/-15 Volt ability accumulation is important too, it charge be adapted and low noise. If the accepted voltage regulator ICs are acclimated I acclaim applicable a column clarify consisting of a 10 ohm resistor and a 470 uF capacitor to abolish any babble generated in the ICs (as apparent in Figure 1). Some 7815 ICs could be awash as babble generators, the adjustable voltage ones (LM317, LM337) are actual abundant quieter. A distinct regulator lath may be acclimated to ability assorted preamps, with anniversary preamp accepting its own column clarify circuits. Because of the all-encompassing clarification applied, the P05 (Rev-A) ability accumulation is recommended for this preamp.

Good affection apparatus should be acclimated with metal blur resistors in the collectors and emitters of the ascribe pairs for atomic noise. Where a resistor has cogent DC voltage imposed on it in aerial accretion circuits consistently use low babble types. Metal blur resistors are about the best alone bettered by wire anguish which is a bit impractical. Abstain cermet, metal glaze, and actual old carbon agreement types. Also abstain bean tantalum capacitors, as they go adulterated and crackle. They are aloof about the best brittle cyberbanking apparatus made. The 100nF capacitor (C6) should be army as abutting as accessible to the opamp accumulation pins - a bowl cap is recommended for best bypass achievement at aerial frequencies.

The 1000uF capacitor can be a accustomed electrolytic of 10 or 16 volts rating. There is usually no botheration with aught DC bent on avant-garde electros. All added electros should be 25V appraisement as a minimum.

Upon blockage the appear specs for the SSM2017 in commendations to noise, my branch adaptation of the preamp measures at atomic as acceptable with a 200 ohm antecedent attrition (typical of best activating microphones).

EIN = 0.27 uV rms in 20 kHz bandwidth with 200 ohm source.
= 1.9 nV per root Hz (equal to spec for SSM2017)
Noise Figure = 0.9 dB rel 200 ohms.

By Phil Allison