LOW POWER FM TELEPHONE BUG
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Mini audio amplifier circuit
This is a mini-sized power amplifier rated at 2 watts OTL that utilizes the LM380 integrated circuit. It serves as a ready-made circuit for audio applications and communication, requiring minimal external equipment. The capacitor C6 can be selected from a...
Low Power Negative Car Power Supply
I have had a lot of queries about getting a low power negative supply in cars, to power Linkwitz transform circuits and the like. There is a switchmode converter, but I must admit that it is overkill for what most...
50 kHz FM Optical Receiver
Frequency modulation (FM) can be used to transmit an analog voltage level signal with good noise immunity. The transmission itself might employ different techniques.
Frequency modulation (FM) is a method widely utilized in communication systems to encode information in a carrier...
transmitter circuits 4
If the audio input is a microphone, it is expected to precede an amplifier to achieve an output power of approximately 8W. The amateur seeking to enhance a small transmitter, which is likely already constructed, can utilize this circuit, which...
500KW Transmitter Schematic
The transmitter was designed with redundancy and cutback (reduced power mode) in mind, giving the transmitter more continuity of service. The final amplifier was divided into 3 separate modules, each using four RCA type UV-898 tubes in push-pull parallel making...
Simple Audio Clipper/Limiter
For use with headphones, this circuit sets the audio clipping level via a 5-kOhm potentiometer. This type of noise clipper is most effective for pulse-type noise with a low duty cycle, such as ignition noise. The resistor Rl establishes the...
Video/Audio Wireless Transmitter
In this fast-paced world, there is little time for inconveniences and a greater need for portability and adaptability. The idea for an Audio/Video transmitter stems from this need. There may have been times when you’ve wanted to hook up your...
Telephone Hold Circuit Circuit
When the switch SI is pressed, the silicon-controlled rectifier (SCR) is activated, connecting LED1 and resistor R1 across the telephone line. This action causes the line voltage to drop to approximately 20 volts, which maintains the connection to the central...
100W Medium Frequency Transmitter
The 100W4 is a two-tube medium frequency transmitter designed for pre-tuning to three frequencies within the medium frequency band, supporting emissions types A1, A2, and A3. In the A1 configuration, both tubes function as parallel oscillators. For A2 and A3...