Long Range/Distance Infrared Transmitter

Here the long range/distance Infrared transmitter circuit, give you extra power for your Infrared transmitter. The majority of the IR remotes do the job reliably within a range of 5 metres. The circuit complexity increases in case you design the IR transmitter for good operation more than a extended distance, for example, 10 metres. To… Read More »

1Hz Clock Generator with Chip On Board (COB)

This is the 1Hz clock generator circuit with Chip On Board (COB). Commonly, the circuits to produce 1Hz clock for digital clock and counter circuits applications implement ICs in conjunction with a crystal and trimmer capacitors, etc. Even so, equivalent or improved accuracy could be obtained working with a chip-on-board (COB) device found inside a… Read More »

Good Quality 500M FM Transmitter

This the Good Quality FM transmitter for your stereo or any other amplifier gives you a pretty good signal strength up to a range of 500 metres having a power output of about 200 mW. This circuit can be operated with a 9V battery. The audio-frequency modulation stage is constructed close to transistor BF494 (T1),… Read More »

Multitone Siren Alarm

Here the simple schematic of multitone siren alarm circuit. This multitone siren is effective for reverse horns, burlgar alarms, and many others. It generates five various audio tones and is much more earcatching than a single-tone siren.

Pyroelectric Fire Alarm System

This is definitely an ultra-sensitive fire sensor that exploits the direct piezoelectric property of an ordinary piezo component to recognize the fire. The lead zirconate titanate crystals within the piezo component have the property to deform and produce an electrical potential when heated, thus converting the piezo component into a heat sensor. The circuit mentioned… Read More »

4 Stage FM Transmitter

This is the FM transmitter circuit which apply 4 radio frequency stages, that are a VHF oscillator designed around transistor BF494 (T1), a preamplifier designed around transistor BF200 (T2), a driver designed around transistor 2N2219 (T3) and also a power amplifier designed around transistor 2N3866 (T4). A condenser microphone is wired at the input of… Read More »

Seismic / Vibration Sensor

This is the circuit diagram of seismic / vibration sensor. The circuit simulates a seismic sensor to detect vibrations/sounds. It’s really sensitive and may detect vibrations due to the motion of animals or human beings. So it could be utilized to monitor protected locations to restrict entry of undesirable individuals or animals. The circuit applies… Read More »

Hi-Fi Compressor with Pre-emphasis

Here is the Hi-Fi compressor circuit with pre-emphasis. The above diagram is a circuit for a high fidelity compressor which uses an external op-amp and has a high gain and wide bandwidth. An input compensation network is required for stability.


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