Repository-circuits
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Here`s how to build your own adjustable power supply based on LM317. The IC LM317 is so versatile that an almost unlimited number of different, small, high grade power supply circuits can be built using it. The configurations can be introduced for different.... -
Several years ago, National Semiconductor came up with some very high performance, easy to use audio power amplifier LM3886 circuits. I needed an extra amp so I can bi-amp some of my homemade electrostatic speakers so I tried the LM3886 chip. LM3886.... -
Here`s a 2x60W LM4780 Power Amplifier. LM3886 is very interested in our project was the first project, and were acclaimed. But the feedback we receive from you, from scratch, we knew we should make a complete device. One reason for that, but hard to find and.... -
Presented here is a Long Range FM Transmitter. This circuit is a super-sensitive, mini-powered FM transmitter consisting of a RF (radio Frequency) oscillator section interfaced with a high sensitivity, wide pass-band audio amplifier and capacitance mike with.... -
Presented FM transmitter bug is built using BF414 / BF324 / BF606 transistor. The 30cm antenna has a range of about 30m in the building, more in the open field. Power supply 2x AAA batteries have been used with voltage of 2.75 V. I added resistor 10K in.... -
Build your own simple mini FM transmitter. This fun project will show you how to build a mini broadcasting transmitter that can transmit an audio signal up to a quarter mile to any FM receiver. It`s easy to build and a good learning experience. It serves as.... -
Here is a very simple telephone broadcaster transmitter which can be used to eavesdrop on a telephone conversation. The circuit can also be used as a wireless telephone amplifier. One important feature of this phone transmitter is that the circuit derives.... -
Presented schematic shows how to build simple PIR motion detector sensor. PIR sensors allow you to sense motion, almost always used to detect whether a human has moved in or out of the sensors range. They are small, inexpensive, low-power, easy to use and.... -
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Here is a very simple project of controlling a small DC-motor (taken from an old personal cassette player) with ATmega8. The ATmega8 is having three PWM channels, out of which two are used here. PWM waveforms are fed to MOSFET (RFD3055) H-bridge. Here,.... -
This RF inductance meter measures RF chokes in the 500 nH to 50 uH range. I needed a way to measure hand-wound RF inductors in my second lab, and since I would only be doing this occasionally, I didn`t need anything fancy, and since once a friend finishes.... -
This easy to build FM transmitter bug can transmit voice to exceptionally good range. Tune trimmer to hear the signal to your near radio. Transmitter frequency range is 88-108 MHz. Max current consumption is 30mA. You can power the fm transmitter bug with a.... -
There are many miniature FM transmitter bug circuits online, this one is unique in that it runs completely on solar power. No battery is required. As long as the sun is shining on the PV panel, the transmitter will transmit. The transmitter bug is useful as.... -
These have two coils and are controlled by changing the direction of the current flow through the coils in the proper sequence. These motors have only four wires and cannot be connected to this kit. See our Kit 1406 for a Bipolar Stepper driver Kit. 2..... -
I built my first power amplifier when I was still in secondary school. The circuit was made of transistors, didn`t provide much power and had an ugly PCB. Around the same time I got access to a datasheet of TDA1524, a tone/volume control circuit, and I.... -
A high quality stereo FM transmitter circuit is shown here. The circuit is based on the IC BA1404 from ROHM Semiconductors. BA1404 is a monolithic FM stereo modulator that has built in stereo modulator, FM modulator and RF amplifier. The FM modulator can be.... -
The circuit is based on the IC BA1404 from ROHM Semiconductors. BA1404 is a monolithic FM stereo modulator that has built in stereo modulator, FM modulator, RF amplifier circuitry. BA1404 FM transmitter can be operated from 76 to 108MHz and power supply for.... -
This TV transmitter transmits audio and video signal from Camcoder Camera, DVD, VHS, Satellite, video game, etc. Playing them in a channel free from the strip of VHF. These signal can be radiated with a common antenna and captured in an it distances of until.... -
This is a TV transmitter for transmitting video of various video sources such as video cameras, Satellite receivers, DVD players, game consoles, etc. TV transmitter`s circuit is working on the 470-580 MHz frequency and can be received on UHF channels 21-34..... -
The USB-Servo is a device to control a servo via USB. A servo is a motorized device that is commonly used in remote controlled cars and planes. I built this device to activate a toy puppet. The puppet has a button on its bottom, if you press the button the.... -
This is USB sound card with PCM2902 chip. For the purpose of testing the D / A converters, I built a simple USB sound card with the circuit PCM2902. The card has analog input and output, an electrical S / PDIF output, galvanically separated input and optical.... -
This HD TV UHF wideband amplifier(Ultra High Frequency amplifier) has a total gain of 10 to 15 dB in the 400 ? 850 MHz domain frequency so it can be used where the tv signal is weak. For this UHF antenna tv amplifier to work correctly you need to cut the.... -
Field strength meter is extremely useful when working with RF devices. It can be used to quickly diagnose whether a transmitter circuit is working, and can be used to detect RF signals in the environment. The simplest field strength meter could be built with.... -
This circuit was submitted by Lazar Pancic from Yugoslavia. The sound card for a PC generally has a microphone input, speaker output and sometimes line inputs and outputs. The mic input is designed for dynamic microphones only in impedance range of 200 to.... -
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Add some resistors in parallel connection for more audio input. To adjust the volume for each input channel, add linear trimmer or potentiometer with configuration: pin1> ground; pin2>output; pin 3>input.. -
This is powerful siren circuit diagram. You can get lots of supports from this circuit because you can use this circuit for your alarm circuit then you will be able to get maximum results... -
Enhancements include: analog front end, pin-to-pin compatibility (for existing designs), analog stabilized comparator and simplified external circuit design, improved time and temperature measurement and reduced current. TDC-GP21 is perfectly suited to.... -
When speaking of fan control, there are generally 2 ways of doing it, linear control, and pulse-width control. The linear control is the most common. The idea is to decrease the voltage to the fan. If the fan is specified to 12 volts, in most cases you can.... -
This is a very small telephone exchange attached only two ordinary Tele phones. Fully bi-directional facility with an intercom system. When a phone is in off hook condition, Exchange will detect it & send ringing pulse to other phone. When it will be picked....
New Circuits
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This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is.... -
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to.... -
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This.... -
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the.... -
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,.... -
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the.... -
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power.... -
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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This controller is essentially 3 pairs of LED sensors in a 3G -bridge configuration. The driver...
For convenience of use at night the receiver is provided with a scale bias lighting and the...