FM Tracking transmitter

jacky March 8, 2012 12 Comments
Description. The circuit presented her will transmit a audio tone in the FM  band. The circuit can be used as a tracking signal transmitter or a remote control transmitter. The circuit uses only easily available components and any one can build this. The transmitter has a range of 100m @ 9V supply, with a matching antenna. The NE555 timer (IC1) is used for producing the audio tone. The first JFET (Q1) is wired as a Hartley oscillator which is...
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Low cost fire alarm circuit.

admin January 21, 2014 89 Comments
Description. When there is a fire breakout in the room the temperature increases. This ultra compact and low cost fire alarm senses fire breakout based on this fact. Transistor BC177 (Q1) is used as the fire sensor here. When the temperature increases the leakage current of this transistor also increases. The circuit is designed so that when there is an increase in the leakage current of Q1, transistor Q2 will get biased. As a result when there is a...
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Aircraft radio circuit

admin January 24, 2012 9 Comments
Description. Here’s a low cost radio circuit that can be used to listen to the radio conversations between aircrafts. The radio circuit based on transistor 2N918 and diode 1N82 receives in the 220Mhz to 400Mhz range. Capacitor C1 and inductor L1 forms the tank circuit for tuning. Diode D1 performs the detection. Transistor T1 performs the necessary amplification. The out put audio signal is just enough to drive a small headphone. For driving speakers. Circuit diagram with Parts list. ...
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AM Transmitter circuit

admin February 28, 2011 81 Comments
Simple AM Transmitter Description Here is the circuit diagram of a simple AM transmitter circuit that can transmit your audios to your backyard.This circuit is designed with limited  power output to match the FCC regulations and still produces enough amplitude modulation of voice in the medium wave band to satisfy your personal needs.You will love this!. The circuit has two parts , an audio amplifier and a radio frequency oscillator. The oscillator is built around Q1 (BC109) and related...
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Single chip FM transmitter circuit

admin February 24, 2011 20 Comments
Single chip FM transmitter Description Here’s a single chip FM transmitter circuit using Maxim semiconductors IC MAX2606. The MAX2606 is a compact, high-performance intermediate frequency VCO specially designed for wireless communication circuits. They have monolithic construction with low-noise and a low-power operation in a compact 6-pin SOT23 packing .Th1s low-noise IC feature an on-chip varicap diode and feedback capacitances that avoid the need for external tuning components, making the MAX2606 perfect for portable systems. Only an external inductor is...
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Single Chip FM Radio circuit

admin February 22, 2011 87 Comments
Single Chip FM Radio Description. Here is a compact low cost FM radio circuit using IC TDA 7000. This circuit is designed as per the data sheet and the result is excellent.Ideal for all category of electronic enthusiasts. The TDA7000 is a monolithic integrated circuit for mono FM portable radios, where a minimum on peripheral components is crucial. The IC TDA 7000 has a Frequency-Locked-Loop system with an intermediate frequency of 70 kHz. The intermediate frequency selectivity is achieved...
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Direct Coupled Radio

admin February 22, 2011 1 Comment
Direct Coupled Radio Circuit Description Here is the circuit of an excellent direct coupled radio ideal for listening to near by stations.The circuit uses Q1 as a diode detector and first audio amplifier.The detection is across the first emitter base junction which operates as a diode.The base emitter capacitance provides the radio filtering.The resistor R1 is adjusted to obtain the least distortion with consistent volume.Transistors Q2 and Q3 also serve as audio amplifiers. Radio Circuit Diagram with Parts List...
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Metal detector circuit

Metal Detector Circuit

jacky July 25, 2018 42 Comments
Metal Detector Circuit I always wanted to make a metal detector seeing how cool it was in all Hollywood, Bollywood movies. One thing I realised is; things aren’t as difficult as you think it is. After all, I found that a metal detector is really simple and easy to make. So in this post, I am sharing with you “How to make a metal detector” Description This is the circuit diagram of a low cost metal detector using a...
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Simple Radio Circuit using Op Amp

admin April 11, 2011 11 Comments
Simple Radio Circuit Description This is a low cost simple radio circuit  based on op amp which can be used to listen to nearby stations. A simple op-amp radio basically consists of a crystal radio along with a fairly sensitive audio amplifier. The audio amplifier is able to receive strong stations around Los Angeles with a minimal 15 foot antenna. Stronger signals are always provided by longer antennas.But the main disadvantage is that in the case of long antennas...
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Radio Collar Transmitter

admin April 27, 2011 No Comments
Radio Collar Transmitter Description This is the circuit diagram of a radio transmitter suitable for fitting on radio collars.The circuit transmits a pulse in the FM between band 88MHz to 105Mhz , which can be adjusted.IC Ne 555 is wired as an astable multivibrator for producing the tone.L1 ,C3 and Q1 forms the modulator.Q2 performs the final power amplification. Notes For the inductor make 5 turns of .5 mm dia insulated copper wire on a standard ball pen refill.Remove...
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