Schematic & Wiring Diagram

Led 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.

Relay 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.

FM 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.

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

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

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

• 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.

Melody 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

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.

5V 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

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

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.

68W Power Amplifier using LM3886

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%.

Audio 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.

Parallel 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.

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.

3W 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.

• 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.

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.

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.

Powerful 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.