Sunday, September 30, 2012
20W Car Audio Amplifier with LM1875
This is just addition 20W audio amplifier circuit , but this time based on the LM1875 audio amplifier IC from National Semiconductors. With a 25V bifold ability accumulation LM1875 can bear 20W of audio ability into a 4 ohm speaker. The LM1875 requires actual beneath external components and has actual low distortion.The IC is aswell arranged with a lot acceptable appearance like fast bulk rate, advanced accumulation voltage range, top achievement current, top achievement voltage swing, thermal aegis etc. The IC is accessible in TO-220 artificial ability amalgamation and is able-bodied acceptable for a array of applications like audio systems, servo amplifiers, home theatre systems etc.
Notes.
- Assemble the circuit on a good quality PCB.
- Use +/-25V DC dual supply for powering the circuit.
- K1 can be 4 ohm, 20W speaker.
- A proper heat sink is necessary for the IC.
- F1 and F2 are 2A
Saturday, September 29, 2012
Here is a simple Audio Booster
This is a simple and low-cost audio booster circuit design. The circuit is based on general purpose amplifier and switches, 2N3392 transistor packed in TO-92. This circuit should be installed before power amplifier module.
To get the maximum audio performance, use metalfilm resistors, MKM and tantalum capacitors which have small tolerance of its value. Also, use stabilized and regulated 9V power supply for better result. You can simply use LM7809 IC regulator on 12V power supply to get stabilized 9V output. The 100K variable resistor is used to adjust the volume, you may remove this component and use main volume in your audio system.
Friday, September 28, 2012
50W Power Amplifier circuit based on STK-1050
STK-1050 Features:
STK1050 has some features that make it superior and good for your audio amplifier.
- Does not require externally connected emitter resistors.
- Values of emitter resistors have carefully been reviewed to provide superior characteristics.
- Better supply voltage utilization permits designing power supply voltage that are about 0.7V (for RL=4ohms) lower than those required for previous DPP models.
- Maximum allowable power consumption for each resistor is 5W or higher, permitting accomodation for all loads.
- Peak allowable current is 18A or more, providing an ample margin even for peak currents under when short circuited or similar emergencies.
- In particular, maximum output 4 ohms have been enormously improved.
- Use of emitter resistors facilitates meeting different safety standards and designing PCBs
- Mutual interferences in the high-frequency range caused by layout of externally connected emitter resistors no longer exist. This facilitates lower distortion factors.
- Pins are used for emitter resistor output terminals that were not conected in previous DPPs. All other terminals remain uncharged; there is no need for major circuit board changes.
Portable headphone amplifier circuit
This is an easy built portable headphone amplifier circuit. You can use this headphone amplifier to amplify your radio receiver, mp3/mp4 player, computer or dvd/cd player. You may connected the input channel directly to those devices.
R3 value was calculated for headphone impedance up to 300 Ohms. Using 600 Ohms loads or higher, change R3 value to 100K.
Take a note that above circuit only show single channel.
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R1 _______________ 10K
R2 _______________ 100K
R3 _______________ 68K (see notes)
R4 _______________ 1K5
R5 _______________ 3K3
R6 _______________ 330R
R7 _______________ 4K7
R8 _______________ 2R2
C1 _______________ 1uF 63V
C2 _______________ 100uF 25V
C3 _______________ 470uF 25V
Q1 _______________ BC239C 25V 100mA NPN High-gain Low-noise Transistor
Q2 _______________ BC337 45V 800mA NPN Transistor
Q3 _______________ BC327 45V 800mA PNP Transistor
J1 _______________ Stereo 3mm. Jack socket
SW1 _______________ SPST Switch
B1 _______________ 3V Battery (2xAAA)
R3 value was calculated for headphone impedance up to 300 Ohms. Using 600 Ohms loads or higher, change R3 value to 100K.
Take a note that above circuit only show single channel.
Thursday, September 27, 2012
TDA2040 - 20W HI-FI Audio Amplifier
Here the hi-fi power amplifier circuit which will deliver 20W power output. This amplifier circuit use single power IC TDA2040 and a few external components.
Detailed explanation about this 20W Power Amplifier
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Detailed explanation about this 20W Power Amplifier
Dynamic Mic Amplifier (To Use Speaker as Microphone)
This is the circuit diagram of dynamic mic amplifier. This simple and easy built circuit can be used as a subtitute of an electret microphone. It will turn an ordinary mini speaker to become a pretty sensitive microphone.
Any NPN transistors can be applied for this circuit, for example: BC547. The circuit will operated from 3v to 9v DC supply. The amplifier configuration used in this dynamic mic amplifier is a common-base amplifier, it accepts the low impedance of the speaker to deliver a gain of more than 100 times.
Wednesday, September 26, 2012
60W Inverter Circuit
Above circuit is a inexpensive completely transistorised inverter circuit ideal for driving medium loads of the order of 40 to 60 watts working with battery of 12V, 15 Ah or bigger power capacity.
Transistors T1 and T2 (BC548) make a 50Hz multivibrator. For having proper frequency, the values of resistors R3 and R4 may have to be modified after testing. The complementary outputs from Collectors of transistors T1 and T2 are provided to PNP darlington driver stages formed by transistor pairs T3-T4 and T6-T7 (utilising transistors BD140 and 2N6107). The outputs from the drivers are given to transistors T5 and T8 (2N3055) connected for push-pull operation.
Considerably bigger wattage could be achieved by growing the drive to 2N3055 transistors (by lowering the value of resistors R7 and R8 while increasing their wattage). Appropriate heatsinks may be applied for that output stage transistors to prevent the transistor from overheating. Transformer X1 is really a 230V primary to 9V-0-9V, 10A secondary used in reverse.
Download the document about this 12VDC to 230VAC 60W Inverter Circuit Here
Stereo PLL FM Transmitter based BH1417
Here the circuit diagram of stereo PLL FM transmitter based BH1417 chip. This is certainly the most recent BH1417 FM Transmitter design diagram from RHOM that consists of lots of capabilities in a single tiny package. It includes pre-emphasis, limiter to ensure that the music can be transmitted at the same audio level, stereo encoder for stereo transmission, low pass filter that blocks any audio signals above 15KHz to avoid any RF interference, PLL circuit that delivers rock solid frequency transmission (no extra frequency drift), FM oscillator and RF output buffer.
There is certainly 14 possible transmission frequencies with 200KHz increments that you can select using a 4-DIP switch. Lower band frequencies begin from 88.7 up to 89.9 MHz, and upper band frequencies begin from 107.7 up to 108.9 MHz.
BH1417 could be supplied with 4 - 6 voltage and needs only about 30mA, giving 20mW output RF power. BH1417 delivers 40dB channel separation that is fairly good, although older BA1404 FM Transmitter chip delivers slightly better 45dB channel separation.
BH1417 is only offered in SOP22 IC case so this may possibly be an inconvenience for some people. On the other hand, since the chip is smaller than common DIP-based ICs it's possible to fit the whole transmitter on a compact PCB.
BH1417 chip may possibly also be applied a stand alone stereo encoder. The benefit of that's that you have full freedom of working with a transmitter and amplifier of your choice. You will still have a pre-emphasis, limiter, stereo encoder and low pass filter in a single tiny package since very few external components are required for these blocks. PIN 5 is MPX output that could be directly connected to an external FM transmitter through a 10uF capacitor.
Detailed information about this circuit, visit: http://electronics-diy.com/BH1417_PLL_Stereo_FM_Transmitter.php . The kit of stereo PLL FM transmitter based BH1417 also available there.
Tuesday, September 25, 2012
Cricket Chirping Sound Generator
This is the circuit diagram of cricket chirping sound generator based on IC 4060, a 14 stage ripple counter and oscillator IC. A suitable audio wave form is produced by IC2 and related electronic components, driving the mini speaker through Q1. To allow a more real-life behavior, the chirp is interrupted in a pseudo-casual way by two timers built around IC1C and IC1D, whose outputs are mixed into IC1B and further time-delayed by IC1A, driving the reset pin of IC2.
An optional Photoresistor can be wired across this pin and positive supply, it is to make the circuit operates in the dark and stops when light is coming, thus imitating the cricket's behavior even more closely. R9 acts as volume control and can be a preset trimmer or a small potentiometer.
Components List:
R1 = 330K 1/4W
R2 = 220K 1/4W
R3,R6 = 100K 1/4W
R4 = Photo resistor (Optional, see text)
R5,R7 = 22K 1/4W
R8 = 10K 1/4W
R9 = 470R 1/2W Trimmer Cermet or Carbon
R10 = 22R 1/4W
C1,C2,C3 = 47µF/25V
C4 = 10µF/25V
C5 = 1µF/50V
C6 = 10nF/63V
D1,D2,D3,D4 = 1N4148
Q1 = BC547
IC1 = 4093
IC2 = 4060
SPKR = 8 Ohm
SW1 = SPST Toggle or Slide Switch
B1 = 9V PP3 Battery (See Notes)
Circuit Notes:
- The circuit can be powered by any battery or power supply adapter with 5 - 12V range.
- For maximum performance results please use a loudspeaker as small as possible.
- In some cases, the chirp can be improved further on by pressing the loudspeaker against a flat surface, for example. a wooden table.
Monday, September 24, 2012
10W Audio Amplifier circuit based on TDA1910
Simple and cheap, that's the advantage of this circuit. Although the output power is not high but audio quality is good, because TDA1910 has a very low noise feature. This circuit suitable for use as a student project.
About TDA1910:
The TDA1910 is a monolithic integrated circuit in MULTIWATT® package, intended for use in Hi-Fi audio power applications, as high quality TV sets.
The TDA 1910 meets the DIN 45500 (d = 0.5%) guaranteed output power of 10W when used at 24V/4W. At 24V/8W the output power is 7W min.
TDA1910 Features:
- muting facility
- protection against chip over temperature
- very low noise
- high supply voltage rejection
- low “switch-on” noise.
Download TDA1910 Datasheet for complete TDA1910 reference
Sunday, September 23, 2012
35W Power Amplifier Circuit using STK082
The following is the schematic diagram of 35W power audio amplifier. Built based on power-amp IC of STK082, this circuit will give great audio output for your home audio system.
Download the STK082 datasheet
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Download the STK082 datasheet
Magnetic Proximity Switch Circuit
Here is the circuit diagram of a magnetic proximity switch that finds a lot of applications in abounding fields.The ambit is based on a alluring reed switch(S1) as the adjacency sensor. A monostable multivibrator based on NE555 (IC1) and a toggle cast bomb based on CD4013 (IC2) does the blow of the circuit. When a allurement is accomplished in adjacency of S1 it closes to accord a abrogating activate at pin 2 of IC1.The achievement of IC1 goes top for a time determines by R2 and C2.This clocks the IC2 active as a toggle cast flop.The achievement (pin 1 ) of IC2 goes top and the transistor Q1 is biased to ON.The broadcast is activated and so do the accessories affiliated to the relay.The LED D1 glows if IC1 is triggered.
When a allurement is accomplished in adjacency of S1 it closes to accord a abrogating activate at pin 2 of IC1.The achievement of IC1 goes top for a time determines by R2 and C2.This clocks the IC2 active as a toggle cast flop.The achievement (pin 1 ) of IC2 goes top and the transistor Q1 is biased to ON.The broadcast is activated and so do the accessories affiliated to the relay.The LED D1 glows if IC1 is triggered.Saturday, September 22, 2012
2x22W Stereo Power Amplifier circuit based TDA1554
This is is a stereo power amplifier circuit works up to 22W on each channel. It will be 2x22W output. A few externel components required to support the main component of TDA1554. Heatsink on the power IC is a must to prevent overheating on the power IC. The chip should run cool enough to touch with the proper heatsink installed.
Operated at 12 Volts and at about 5 Amps at full volume. Lower volumes use less current, and therefore produce less heat. Printed circuit board is preferred, but universal solder or perf board will do. Keep lead length short.
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Component part list:
R1__________39K 1/4 Watt Resistor
C1,C2_______10uf 25V Electrolytic Capacitor
C3__________100uf 25V Electrolytic Capacitor
C4__________47uf 25V Electrolytic Capacitor
C5__________0.1uf 25V Ceramic Capacitor
C6__________2200uf 25V Electrolytic Capacitor
U1__________TDA1554 Two Channel Audio Amp Chip
MISC________Heatsink For U1, Binding Posts (For Output), RCA Jacks (For Input)
Operated at 12 Volts and at about 5 Amps at full volume. Lower volumes use less current, and therefore produce less heat. Printed circuit board is preferred, but universal solder or perf board will do. Keep lead length short.
Positive Variable Power Supply circuit
The following diagram is the schematic diagram of positive adjustable/variable power supply. It means that the power supply output will be DC current with positive [+] and ground [0] polarity.
Schematic diagram:
Power Supply Input:
Component part list:
R1 = 330
R2 = 1K
VR1 = 10K 10-turn trimpot
C1 = 2200uF/50V
C2,4 = 100nF ceramic
C3,4 = 10uF/63V
D1-6 = 1N5403
REG IC = LM317T
Heatsink
Visit this page to download the variable power supply diagram manual.
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Schematic diagram:
Power Supply Input:
Component part list:
R1 = 330
R2 = 1K
VR1 = 10K 10-turn trimpot
C1 = 2200uF/50V
C2,4 = 100nF ceramic
C3,4 = 10uF/63V
D1-6 = 1N5403
REG IC = LM317T
Heatsink
Visit this page to download the variable power supply diagram manual.
Friday, September 21, 2012
FM Transmitter Circuit with MAX2606
FM transmitter circuit which is build using single chip of MAX2606. A very simple FM transmitter connects your home-entertainment system to a portable radio that will be carried surrounding the house and into the back yard. As an example, it is possible to play music on the CD player in your private room, and listen to it on a portable radio by the back-yard barbeque.
IC1 is a voltage-controlled oscillator with integrated varactor. Its nominal frequency of oscillation is set by inductor L1, and a 390nH value places that frequency at 100MHz. Potentiometer R1 then allows you to choose a channel by tuning above the FM band of 88MHz to 108MHz. Output power is about -21dBm into 50 (most nations accept emissions below 10dBm in the FM band).
The home system's left and right audio signals are summed by R3 and R4, and attenuated by the (optional) potentiometer R2. R2's wiper signal serves as a volume adjustment by modulating the RF frequency. Signals above 60mV introduce distortion, so the pot attenuates down from that level.
In the absence of a common FM radio antenna, 75cm (30 inches) of wire will suffice as a transmitting antenna. For most effective reception, it need to be mounted parallel with the receiving antenna. The IC operates on a single power supply voltage inside the range 3V to 5V, but it is best to regulate the applied voltage to reduce frequency drift and noise.
Electronic Code Lock With 1 Transistor
This is of advance the simplest electronic code lock circuit one can make. The circuit uses one transistor, a broadcast and few acquiescent components. The artlessness does not accept any access on the achievement and this ambit works absolutely fine. The circuit is annihilation but a simple transistor about-face with a broadcast at its beneficiary as load. 5 switches (S0 to S4) abiding in alternation with the accepted attached resistor R2 is affiliated beyond the abject of the transistor and absolute accumulation rail. Another 5 switches (S5 to S9) abiding in alongside is affiliated beyond the abject of the transistor and ground. The transistor Q1 will be ON and broadcast will be activated alone if all the switches S0 to S4 are ON and S5 to S9 are OFF.
Arrange these switches in a confused address on the console and that it. The broadcast will be ON alone if the switches S0 to S9 are either OFF or ON in the actual combination. The accessory to be controlled application the lock circuit can be affiliated through the broadcast terminals. Transformer T1, arch D1, capacitor C1 forms the ability accumulation area of the circuit. Diode D2 is a freewheeling diode. Resistor R1 ensures that the transistor Q1 is OFF if there is no affiliation amid its abject and absolute accumulation rail.
Arrange these switches in a confused address on the console and that it. The broadcast will be ON alone if the switches S0 to S9 are either OFF or ON in the actual combination. The accessory to be controlled application the lock circuit can be affiliated through the broadcast terminals. Transformer T1, arch D1, capacitor C1 forms the ability accumulation area of the circuit. Diode D2 is a freewheeling diode. Resistor R1 ensures that the transistor Q1 is OFF if there is no affiliation amid its abject and absolute accumulation rail.
19W Power Amplifier based LA4440
This is the 19W power amplifier circuit built based power IC LA4440. The LA4440 output configured in bridge connection. The LA4440 can be used for stereo amplifier and it will give power output of 6W on each channel. But if you use this power IC in bridge mode, the it will deliver power audio output up to 19W. Recommended supply voltage is 13.2V, 2A and heatsink should be mounted on the power IC.
Power IC LA4440 Features:
- Built-in 2 channels (dual) enabling use in stereo and bridge amplifier applications.
- Dual : 6W´2 (typ.)
- Bridge : 19W (typ.)
- Small pop noise at the time of power supply ON/OFF and good starting balance.
- Minimum number of external parts required.
- Good ripple rejection : 46dB (typ.)
- Easy to design radiator fin.
- Low distortion over a wide range from low frequencies to high frequencies.
- Small residual noise (Rg=0).
- Good channel separation.
- Built-in protectors.
- Built-in audio muting function.
- Overvoltage, surge voltage protector
- Thermal protector
- Pin-to-pin short protector
Download the database of LA4440
Thursday, September 20, 2012
TDA7295, 80W Audio Amplifier
Below is a schematic diagram of the 80W power amplifier based on single Power IC TDA7295. With simple diagram, this circuit will be easy to build.
The IC TDA7295 is a monolithic integrated circuit , intended for use as audio class AB amplifier in Hi-Fi field applications such as home theatre and topclass TV.
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The IC TDA7295 is a monolithic integrated circuit , intended for use as audio class AB amplifier in Hi-Fi field applications such as home theatre and topclass TV.
Basic Oscillator Circuit using Two Transistors
This is the schematic diagram of basic oscillator circuit which using two transistors. When two transistors and a couple of passive components are connected as shown in the figure, the circuit starts to oscillate. The frequency of oscillation can be adjusted by changing the values of either the resistor or the capacitor.
For easier experiment, you may replace the resistor with 10K potensiometer. By increasing its frequency to a suitably high level, it can be used to drive a speaker or a buzzer to produce an audio alarm note. By sufficiently reducing its frequency, the circuit may be used to flash a LED as a warning indicator.
The another circuit of two transistors oscillator described in the following video:
Tuesday, September 18, 2012
Ramp Generator With 555 Timer IC
We apperceive that if a capacitor is answerable from a voltage antecedent through a resistor, an exponential waveform is produced while charging of a capacitor from a connected accepted antecedent produces a ramp. This is the abstraction abaft the circuit. The circuit of a access architect application timer 555 is apparent in figure. Here the resistor of previous circuits is replaced by a PNP transistor that produces a connected charging current.Charging current produced by PNP constant current source is
iC = Vcc-VE / RE
where VE = R2 / (R1 + R2) * VCC + VBE
When a trigger starts the monostable multivibrator timer 555 as shown in figure, the PNP current source forces a constant charging into the capacitor C. The voltage across the capacitor is, therefore, a ramp as illustrated in the figure. The slope of the ramp is given as
Simple FM Radio Receiver Circuit with TDA7021T
| R1 = 8kΩ2 R2 = 10kΩ R3 = 390Ω C1,C3 = 10nF C2,C6,C9,C16 = 100nF C4 = 33pF C5 = 25pF trimmer (Murata type TZB4Z250AB10R00) C7,C10 = 1nF5 C8 = 820pF | C11 = 1nF C12 = 68pF C13 = 220pF C14 = 47μF 10V (Nichicon UWX1A470MCL1GB 5.5mmL chip type) C15 = 3nF3 L1 = 36nH (4 turns 0.5mm silver-plated wire, inside diameter 4mm; length 7mm) L2 = 1μH, SMD case 0805 (fres > 300 MHz) IC1 = TDA7021T (SMD in SO16 case) |
Complete explanation, visit this site
Monday, September 17, 2012
1.2Watt Mini Audio Amplifier Circuit based KA2214
This mini audio amplifier circuit is based on power IC KA series. This mini amplifier delivers dual audio output (stereo) at 1.2W on each channel.
The KA2214 is a monolithic integrated dual audio power amplifier in a 14-pin plastic dual in line package. It is designed portable audio sets.
Download the KA2214 datasheet for detail features and specifications.
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Download the KA2214 datasheet for detail features and specifications.
Saturday, September 15, 2012
Triangle Wave and Square Wave Generator
This is a simple circuit diagram of triangle wave and square wave generator.
The circuit is designed based on a common 1458 dual op-amp that can be used from very low frequencies to about 10 Khz. The time interval for one half cycle is about R*C and the outputs will supply about 10 milliamps of current. Triangle amplitude can be altered by adjusting the 47K resistor, and waveform offset can be removed by adding a capacitor in series with the output.
source of Triangle Wave and Square Wave Generator circuit:
http://www.high-voltage-lab.com/211/triangle-squarewave-generator
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The circuit is designed based on a common 1458 dual op-amp that can be used from very low frequencies to about 10 Khz. The time interval for one half cycle is about R*C and the outputs will supply about 10 milliamps of current. Triangle amplitude can be altered by adjusting the 47K resistor, and waveform offset can be removed by adding a capacitor in series with the output.
source of Triangle Wave and Square Wave Generator circuit:
http://www.high-voltage-lab.com/211/triangle-squarewave-generator
Easy Build RF Transmitter
This circuit most likely the easiest and simplest radio transmitter which you will get anyplace. It uses total of 5 components and could be built into a really compact space. It's very good for science fair projects or other science related projects in which a small range transmission is useful.
It works on 1.5 to 3 V, with small hearing aid battery packs or lithium "coin" cells becoming excellent. A thermistor or photoresistor may be inserted in series with R1 to get a various output frequency depending on the input.
The frequency may also be adjusted by modifying the value of C1. A 2N2222 transistor is highly recommended, but you are able to try out other types as well. Performance is likely to vary from type to type as well as from transistor to transistor. L1 is 20 to 30 turns of thin magnet wire (24 to 32 ga.) close wound about a 1/8 to 1/4" diameter non-conductive form. The coil is normally tapped 1/3 of the way from one end and also the tap connected to the emitter of Q1. Try out with all of the values in this particular circuit. Nothing is vital, but the result may be varied considerably.
Friday, September 14, 2012
One Transistor LED Flasher Circuit
Here the schematic diagram of one transistor LED flasher. This circuit can be the simplest circuit led flasher over the world.
This is a novel flasher circuit working with a single driver transistor that will take its flash-rate from a flashing LED. The flasher in the photo is 3mm. An ordinary LED is not going to work. The flash rate are not able to be altered by the brightness of the high-bright white LED can be adjusted by replacing the 1k resistor across the 100uF electrolytic to 4k7 or 10k.
The 1k resistor discharges the 100uF so that when the transistor turns on, the charging current into the 100uF illuminates the white LED. If a 10k discharge resistor is applied, the 100uF will not be completely discharged and also the LED isn't going to flash as bright.
All of the components within the photo are in the identical places as in the circuit diagram in making it easy to learn how the components are joined.
Thursday, September 13, 2012
LM3886 , 100W Power Audio Amplifier circuit
The following circuit diagram is the 100 Watt power audio amplifier circuit, build based on power amp chip LM3886. The single chip of IC LM3886 is able to amplify the audio power output up to 68W.
In this circuit, the two of LM3886 are paralled to gain more powerful amplifier output. This amplifier can deliver about 50W into a 8-ohm speaker and 100W into a 4-ohm speaker. To make a stereo amplifier, there are should be use 4 pieces of LM3886.
15W Audio Amplifier with STK055
Here the schematic diagram of 15W audio amplifier, built based on single power chip STK055 from Sanyo.The STK055 is old power amplifier chip which still available on the market because of the ease of its usage and the performance is good. This chip requires heatsink to be mounted on its body.
Technical details:
- Maximum power supply: ± 28V
- Recommended supply voltage: ± 20V
- Power output: 15W
- RL: 8 Ohm
- TDH: 0.3%
- Rin: 52K
- Gain: 26.4 dB
- Noise: 0.3mV
Simple FM Transmitter
This FM transmitter claimed to be a very good transmitter. This circuit is worked very well since this circuit is actually copied from available electronic kit.
Component part:
Frequency range is 100-108 MHz. The circuit is only mono circuit, and accepts an audio input from either a microphone or other source. The input impedance is 1Mohm. The input sensitivity is 5mV and the max input signal is 10mV. The transmitted signal can be picked up on a FM radio. The circuit can be used for short-range transmission, eg. for wireless microphones.
The power supply to use is 9-14 V DC, one of the little rectangular 9V batteries is fine. Connect this to the + and - points on the PCB. The sound input goes to the points marked "MIKE". The antenna should be connected to the point marked "ANT". The emitter's output impedance is 50 ohms. You can make your own fancy antenna if you like.
Source: http://www.high-voltage-lab.com/77/small-radio-transmitter
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Component part:
R1 100K R2 220K R3 22R R4 1K trimmer R5 1K R6 56K R7 1M R8 1K2 T1 BF244A or BF245A FET T2 2N3819 FET T3 BC307/8/9 or BC557/8/9 PNP | D1 Varicap diode (eg. BB119) D2 1N4148 C1 5pF ceramic C2 6pF ceramic C3 15pF ceramic C4 trimmer cap C5 15pF ceramic C6 1nF ceramic C7 100uF electrolytic C8 4.7uF electrolytic C9 100pF ceramic |
Frequency range is 100-108 MHz. The circuit is only mono circuit, and accepts an audio input from either a microphone or other source. The input impedance is 1Mohm. The input sensitivity is 5mV and the max input signal is 10mV. The transmitted signal can be picked up on a FM radio. The circuit can be used for short-range transmission, eg. for wireless microphones.
The power supply to use is 9-14 V DC, one of the little rectangular 9V batteries is fine. Connect this to the + and - points on the PCB. The sound input goes to the points marked "MIKE". The antenna should be connected to the point marked "ANT". The emitter's output impedance is 50 ohms. You can make your own fancy antenna if you like.
Source: http://www.high-voltage-lab.com/77/small-radio-transmitter
Wednesday, September 12, 2012
Pipe Bomb Mic Construction
Pipe Bomb Mic Construction, by Jamie Heilman:
My own dimensions for my prototype are X= 36cm, Y= 5.5cm. This imparted a fairly high pitch tone but I like it.
The X and Y dimensions really should be played with to develop the precise tone your seeking, also I chose a telephone loudspeaker as well as a crystal mic so I got the funkiest tone I could think of. A dynamic microphone might limit the treble somewhat most likely make it sound less harsh. I’d be considering any mods produced to this style (ie. stories, suggestions, etc.) so feel free to e mail me.
The amps may be any old easy op-amp construction that can drive a loudspeaker or take a mic input. I just made use of some excess material I had lying around to make mine. The end product had all the circuitry inside the tube and the battery pack on the outside, with one control for the gain of the loudspeaker (mic was at fixed gain).
Note, in case you locate this in the front of the amplifier and turn every thing up, without having adding any dampening to the pipe, it will feedback just like you wont imagine! You'll most likely wish to keep away from this because it tends to hurt your ears. I put a bit of foam rubber in one end of the tube and an old sock in the other to dampen feedback. I like to leave my alternatives open though, so I also didn’t make this a permanent addition. My prototype is essentially a fuzz, as my guitar will overload the loudspeaker fairly simply and the pipe just adds a bit of strange overtone and what I believe is the smallest hint of reverb. Sounds excellent though! Clean tones via a similar set up would sound good too, but I haven’t constructed one of those yet. Possibly a larger speaker (4-5") and an old carpet pipe would probably add improved characteristics for clean tones. Attempt changing the tube material also for a various tone, I almost applied a bit of gutter piping when I 1st built this, right now I wonder what it would’ve sounded like.
Download the document about how to build Pipe Bomb Mic in PDF file:
Download Link
ReadMore[..]
My own dimensions for my prototype are X= 36cm, Y= 5.5cm. This imparted a fairly high pitch tone but I like it.
The X and Y dimensions really should be played with to develop the precise tone your seeking, also I chose a telephone loudspeaker as well as a crystal mic so I got the funkiest tone I could think of. A dynamic microphone might limit the treble somewhat most likely make it sound less harsh. I’d be considering any mods produced to this style (ie. stories, suggestions, etc.) so feel free to e mail me.
The amps may be any old easy op-amp construction that can drive a loudspeaker or take a mic input. I just made use of some excess material I had lying around to make mine. The end product had all the circuitry inside the tube and the battery pack on the outside, with one control for the gain of the loudspeaker (mic was at fixed gain).
Note, in case you locate this in the front of the amplifier and turn every thing up, without having adding any dampening to the pipe, it will feedback just like you wont imagine! You'll most likely wish to keep away from this because it tends to hurt your ears. I put a bit of foam rubber in one end of the tube and an old sock in the other to dampen feedback. I like to leave my alternatives open though, so I also didn’t make this a permanent addition. My prototype is essentially a fuzz, as my guitar will overload the loudspeaker fairly simply and the pipe just adds a bit of strange overtone and what I believe is the smallest hint of reverb. Sounds excellent though! Clean tones via a similar set up would sound good too, but I haven’t constructed one of those yet. Possibly a larger speaker (4-5") and an old carpet pipe would probably add improved characteristics for clean tones. Attempt changing the tube material also for a various tone, I almost applied a bit of gutter piping when I 1st built this, right now I wonder what it would’ve sounded like.
Download the document about how to build Pipe Bomb Mic in PDF file:
Download Link
Monday, September 10, 2012
Easy LED Flasher Schematic
Here the schematic diagram of Easy LED Flasher circuit:
Parts List:
This circuit will flash a bright or high-brightness red LED (5000+ mcd). Very good for fake car alarm or other attention getting device. Part values are not significant, test something else to start with from your junkbox.Certainly, the 470 ohm resistor (R3) determines the LED's brightness and limits the current supply to around 20mA. R3 value of 390 ohm may also be applied as a save value.
If you decide to go using a green or yellow led, which take more current, you might want to change the 470 ohm with an suitable value. Flash speed is established by R2 and C1 and is roughly three time constants (3*R2*C1). R1 provides bias to Q1 which ought to be small enough not to saturate Q2 with the capacitor disconnected. When the circuit doesn't oscillate, R1 may be very low or R2 too high. D1 allows for highter duty cycle operation and limits the feedback at the base of Q1 to -0.7 volts. D1 might be ommited for low supply power like 6 - 9V and low duy cycle operation.
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Parts List:
| R1 = 10M ohm R2 = 1K – 100K ohm R3 = 470 ohm C1 = 0.47μF – 10μF/25V | D1 = 1N914 Q1 = 2N3904 Q2 = 2N3906 Led = High Brightness Red LED |
This circuit will flash a bright or high-brightness red LED (5000+ mcd). Very good for fake car alarm or other attention getting device. Part values are not significant, test something else to start with from your junkbox.Certainly, the 470 ohm resistor (R3) determines the LED's brightness and limits the current supply to around 20mA. R3 value of 390 ohm may also be applied as a save value.
If you decide to go using a green or yellow led, which take more current, you might want to change the 470 ohm with an suitable value. Flash speed is established by R2 and C1 and is roughly three time constants (3*R2*C1). R1 provides bias to Q1 which ought to be small enough not to saturate Q2 with the capacitor disconnected. When the circuit doesn't oscillate, R1 may be very low or R2 too high. D1 allows for highter duty cycle operation and limits the feedback at the base of Q1 to -0.7 volts. D1 might be ommited for low supply power like 6 - 9V and low duy cycle operation.
Sunday, September 9, 2012
Transistored Stereo Tone Control
Here the circuit diagram of stereo tone control system which also available on the market in circuit kit, you might get the kit at electronic component/part store near your area. The tone control require 12v of supply voltage to work.
The circuit designed based on common tone control circuit, by using two transistors FCS9014 in each channel, so there are actually four transistors in this 12v stereo tone control. Take a note that you need to install the circuit prior to the amplifier device. The output of tone control should be connected towards the input of the audio amplifier. Any small signal NPN transistor such as BC547B, 2N3904, C828, or C945 may be put to use to replace FCS9014.
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The circuit designed based on common tone control circuit, by using two transistors FCS9014 in each channel, so there are actually four transistors in this 12v stereo tone control. Take a note that you need to install the circuit prior to the amplifier device. The output of tone control should be connected towards the input of the audio amplifier. Any small signal NPN transistor such as BC547B, 2N3904, C828, or C945 may be put to use to replace FCS9014.
Saturday, September 8, 2012
32W HiFi Amplifier circuit based on TDA2050
This is a High Fidelify (Hi-Fi) amplifier circuit based on single IC TDA205. This is a mono channel audio amplifier. You need to build the same circuit for stereo channel.
PCB Design:
TDA2050 Description:
The TDA 2050 is a monolithic integrated circuit in Pentawatt package, intended for use as an audio class AB audio amplifier. Thanks to its high power capability the TDA2050 is able to provide up to 35W true rms power into 4 ohm load @ THD =10%, VS = ±18V, f = 1KHz and up to 32W into 8ohm load @ THD = 10%, VS = ±22V, f = 1KHz. Moreover, the TDA 2050 delivers typically 50W music power into 4 ohm load over 1 sec at VS=22.5V, f = 1KHz.
The high power and very low harmonic and crossover distortion (THD = 0.05% typ, @ VS = ±22V, PO = 0.1 to 15W, RL=8ohm, f = 100Hz to 15KHz) make the device most suitable for both HiFi and high class TV sets.
Download TDA2050 datasheet for the circuit reference.
Mice Repellent Circuit
To drive out the mice, you can create an electronic circuit of mice repellent as shown above. With 50KHz frequency generated by the timer IC 555. The mice would run because his ears will feel sore due to the signal frequency.
The work of this circuit is very simple. The timer IC act as the frequency generator, while the frequency value is decided by C1 and C3. The output of 555 will be amplified by the SC1162 transistor and then fed to the speaker so the audio signal can be heard by the mice.
Parts List:
R1 = 1K8
R2 = 1K
R3 = 5K6
R4 = 480R
C1 = 2,2nF
C2 = 0,022uF/6V
IC = 555
Q = SC1162
SP = Speaker 4 ohm
Thursday, September 6, 2012
Guitar Effect Circuit : Electro Harmonix Big Muff Pi
This Electro Harmonix Big Muff Pi circuit would most likely be better making the change by a contemporary input-jack power and a DPDT bypass switch. The kinds of transistors and diodes are unknown. It really is most likely that any high acquire NPN transistor and diode 1N914 will work. Coupling capacitors marked with * have been reported at its greatest if it has altered to 0.1uF and also the capacitors marked with ** modified to one.0UF. The unique transistors had been labeled SPT 87-103, and diodes of origin are marked or 525GY or 523GY (hard to examine.)
Download Electro Harmonix Big Muff Pi schematics in PDF:
Download Link
Static 0 to 9 display With 7490 & 7446 IC
The Ciruit apparent here is of a simple 0 to 9 display that can be active in a lot of applications. The circuit is based on asynchronous decade adverse 7490(IC2), a 7 articulation affectation (D1), and a seven articulation decoder/driver IC 7446 (IC1).
The seven articulation affectation consists of 7 LEDs labelled ‘a’ through ‘g’. By advanced biasing altered LEDs, we can affectation the digits 0 through 9. Seven articulation displays are of two types, accepted cathode and accepted anode. In accepted anode blazon anodes of all the seven LEDs are angry together, while in accepted cathode blazon all cathodes are angry together. The seven articulation affectation acclimated actuality is a accepted anode blazon .Resistor R1 to R7 are accepted attached resistors. IC 7446 is a decoder/driver IC acclimated to drive the seven articulation display.
Working of thiscircuit is actual simple. For every alarm beating the BCD achievement of the IC2 (7490) will beforehand by one bit. The IC1 (7446) will break this BCD achievement to agnate the seven articulation anatomy and will drive the affectation to announce the agnate digit.
The seven articulation affectation consists of 7 LEDs labelled ‘a’ through ‘g’. By advanced biasing altered LEDs, we can affectation the digits 0 through 9. Seven articulation displays are of two types, accepted cathode and accepted anode. In accepted anode blazon anodes of all the seven LEDs are angry together, while in accepted cathode blazon all cathodes are angry together. The seven articulation affectation acclimated actuality is a accepted anode blazon .Resistor R1 to R7 are accepted attached resistors. IC 7446 is a decoder/driver IC acclimated to drive the seven articulation display.
Working of thiscircuit is actual simple. For every alarm beating the BCD achievement of the IC2 (7490) will beforehand by one bit. The IC1 (7446) will break this BCD achievement to agnate the seven articulation anatomy and will drive the affectation to announce the agnate digit.
Wednesday, September 5, 2012
Magic Lights Circuit using Bi-Colour LED
This is the magic lights circuit which use bi-colour LED as the output to provide the light. The circuit uses 14 bi-colour (red and green) LEDs having 3 terminals each. Various dancing colour patterns are generated utilizing this circuit considering that each LED can create three various colours. The middle terminal (pin 2) of the LEDs will be the common cathode pin that is grounded. When a positive voltage is applied to pin one, it emits red light. Similarly, when positive voltage is applied to pin 3. it emits green light. And when positive voltage is simultaneously applied to its pins 1 and 3, it emits amber light.
The circuit could be implemented for decorative lights. The IC1 (timer IC 555) is applied in astable mode of multivibrator to produce clock signal for IC2 and IC3 (CD4518) that are dual BCD counters.
The two counters of each one of these ICs have already been cascaded to acquire 8 outputs from each. The outputs from IC2 and IC3 are connected to IC4 through IC7 that are BCD to 7-segment latch/decoder/driver ICs. Therefore we acquire a complete of 14 segment outputs from each of the IC pairs composed of IC4 plus IC5 and IC6 plus IC7. While outputs from former pair are connected to pin No. 1 of all the 14 bi-colour LEDs through current limiting resistors, the ouputs of the latter pair are similarly connected to pin No.3 of all the bi-colour LEDs to acquire a magical dancing lights effect.
Tuesday, September 4, 2012
20W Bridge Car Amplifier based TDA7240A
The following circuit diagram is a bridge amplifier which specially designed for car audio system. The circuit is very simple with few external components supporting the power IC TDA7240A. This circuit will produce a maximum power output of 20W
PCB Layout:
The circuit diagram and PCB layout come from the IC TDA7240A datasheet. Download TDA7240A datasheet for circuit reference.
3 Channel LED Driver using CAT3063
The circuit diagram of a three channel LED driver circuit using CAT3063 is apparent here. C4 is an ascribe clarify capacitor. R1 is the resistor acclimated for programming the achievement current. C3 is the achievement clarify capacitor. C1 and C2 are the accumulator capacitors of the centralized allegation pump circuit. A argumentation top at pin 5 will accredit the IC and a argumentation low on the aforementioned pin will drive the IC into abeyance mode. In the abeyance mode, the quiescent accepted is about according to zero. With the acclimated amount of R1, the LED accepted per approach will be 25mA.
When powered up the CAT6063 operates in 1X approach i.e, the achievement voltage will be according to the ascribe voltage. If this achievement voltage is abundant to adapt the accepted through all LEDs, the IC charcoal 1X mode. If the achievement voltage is not acceptable abundant to adapt the adapted accepted through the LEDs, the accessory automatically switches to the 1.5X approach area the achievement voltage is 1.5 times the ascribe voltage. This action is again if anytime the IC is powered up or activate from abeyance mode.
Monday, September 3, 2012
Very Easy R/C Circuit
The following diagram is a very easy and efficient receiver for actuating garage doors, starter motors, alarms, warning systems and numerous some other possibilities.
The SCR, that has a extremely low trigger present of 30 uA is common -- it requires an input electric power of just 30 uW to switch on the relay. A high Q tuned antenna circuit assures rejection of spurious signals. A whip or wire antenna is adequate as much as 100 feet from a low power transistor transmitter. A momentary-off switch resets the circuit.
The circuit specifies a whip or wire antenna which just indicates a solid piece of wire 6-12 inches long (15-30cm). The antenna coil is experimental, however you can start with ten to 12 turns of #22 (0.7mm) magnet wire, and 5/16" (8mm) coil diameter. Antenna wire is soldered at 1/2 turn of the coil and the gate of the BRY35 is soldered about halfway the coil. This circuit will transmit as much as 100-feet with the above specs @ 30uA.
The relay coil is specify's as much as 200 ohm but that's just the one I had in stock. Any low-ohm relay, even at 9V or so, ought to accomplish the task. And one remaining note, do not be expecting too a lot from this circuit. The "Very Easy R/C Circuit" is simply that; Easy!
The BRY35 is really an classic semiconductor produced by Philips. A great replacement would be the EC103D1, also produced by Philips (see pin-out picture for this device). NTE Semiconductors gives an alternative of NTE5405, but I have not attempted it. I think, a NTE5400 (30V) or NTE5401 (60V) will function just also. The NTE5405 is a bit overkill at 400V.
ReadMore[..]
The SCR, that has a extremely low trigger present of 30 uA is common -- it requires an input electric power of just 30 uW to switch on the relay. A high Q tuned antenna circuit assures rejection of spurious signals. A whip or wire antenna is adequate as much as 100 feet from a low power transistor transmitter. A momentary-off switch resets the circuit.
The circuit specifies a whip or wire antenna which just indicates a solid piece of wire 6-12 inches long (15-30cm). The antenna coil is experimental, however you can start with ten to 12 turns of #22 (0.7mm) magnet wire, and 5/16" (8mm) coil diameter. Antenna wire is soldered at 1/2 turn of the coil and the gate of the BRY35 is soldered about halfway the coil. This circuit will transmit as much as 100-feet with the above specs @ 30uA.
The relay coil is specify's as much as 200 ohm but that's just the one I had in stock. Any low-ohm relay, even at 9V or so, ought to accomplish the task. And one remaining note, do not be expecting too a lot from this circuit. The "Very Easy R/C Circuit" is simply that; Easy!
The BRY35 is really an classic semiconductor produced by Philips. A great replacement would be the EC103D1, also produced by Philips (see pin-out picture for this device). NTE Semiconductors gives an alternative of NTE5405, but I have not attempted it. I think, a NTE5400 (30V) or NTE5401 (60V) will function just also. The NTE5405 is a bit overkill at 400V.
Sunday, September 2, 2012
AM Receiver circuit with MK484
This is a AM Receiver with single IC MK484. If your are interested to build this radio circuit, you may buy the kits include the component part list at kitsrus.com.
Part list:
| R9, R10_________ 6R8 R6_____________ 100R R3_____________ 1K R1_____________ 4K7 R7_____________ 5K6 R4_____________ 10K R2_____________ 100K R5_____________ 150K R8_____________ 820K Pot_____________ 10K log pot Coil & ferrite bar set | C7______________ 470p ceramic C, C4, C5, C6_____ 470nF monoblock C2______________ 100nF monoblock C3, C8___________ 100uF electrolytic capacitor VariCap__________ 60/160 AM tuning cap D1, D2, D3, D4____ 1N4148 diode Q1, Q3___________ BC548 Q2______________ BC558 IC1_____________ MK484 AM radio IC TO92 Speaker__________ 0.5 or 1W, 8 ohm speaker |
Visit this AM Radio Receiver for more explanation.
Surround Sound Processor Circuit
This is the easy build surround sound processor circuit using the digital delay process method. This audio processor isn't applying any unique function ICs that tough to obtain parsonaly, and designed in only common purpose ICs.
The kind of this Surround Processor is producing the surround impact with processing two channels of stereo supply. The majority of those are generates the surround impact with separates reverberations from supply signal and applies any processes, after which mix it to front channels or output as rear channel.
The circuit works and contains three modules:
Separating the Reverberatins
The distinction in between each channels is separated with distinction amplifier from the op-amp. And greater frequencies inside the distinction signal are cut using the LPF.
A-D and D-A conversion
These are composed with common purpose ICs. The A-D converter is basically delta modurator that making use of a comparator plus a D type flip-flop. And it converts analog signal into digital data of one bit, 2 Msa/sec. Following passed digital delay, the bit stream is directly conversion into analog signal using the integrater.
It isn't beneficial that signal to noise ratio and distortion as this A-D, D-A converter.
Digital Delay
For the digital delay method, a DRAM chip is utilised as a FIFO memory. This circuit design demands a 64K bit DRAM, but I utilized a 256K bit DRAM discovered within the junk box. Shift register generates Read-Modify-Write cycle, read out old data and save new data in a single cycle.
And lower byte in the address counter is assined as row address with the DRAM to increment row address every single cycle, to ensure that refresh cycle is often omitted. The FIFO length is 65536 bits and 2 Msa/sec makes 33 msec of delay time.
Surround sound processor circuit source page: http://elm-chan.org/works/srp/report_e.html
Saturday, September 1, 2012
One Transistor FM Radio
Thi circuit is very simple with only one transistor. No need additional active components, but if you want to hear the sound louder, just build another amplifier circuit... :)
More instruction how to build this circuit, visit this page
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| Part designator | Part description |
| C1a,C1b | 10 pf, 50 v, ceramic disc capacitor |
| C2 | 22 pf, 50 v, ceramic disc capacitor |
| C3 | RF tuning capacitor |
| C4 | 330 pf, 50 v, ceramic disc capacitor |
| C5,C8 | 0.001 uf, 50 v, ceramic disc capacitor |
| C6 | 0.22 uf, 50 v, film capacitor |
| C7 | 0.0047 uf, 50 v, ceramic disc capacitor |
| C9 | 22 uf, 16 v, electrolytic capacitor |
| D1 | TL431AIZ voltage control Zener (shunt regulator) |
| EPH1 | High impedance earphone |
| L2 | 22 uh RF choke |
| Q1 | 2N4416A JFET transistor |
| R1 | 470K, 1/4 w, resistor |
| R2, R3 | 1K, 1/4 w, resistor |
| R4 | 10K, 1/4 w, resistor |
| R5 | 1M, 1/4 w, resistor |
| R6 | 100 ohm, 1/4 w, resistor |
| S1 | Small SPST switch |
| screws for C3 | screws for mounting C3 (2 needed) |
| nylon screw | #4 nylon screw used for tuning C3 |
| battery connector | mini battery snap |
More instruction how to build this circuit, visit this page
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