Free Simple Circuit Diagram
Balanced signal consist of two lines that have opposite phases, and should be received with differential input receiver. Balanced signal is employed in many telecommunication techniques to improve transmission system’s noise immunity. Balanced signal is usually transmitted in twisted pair cables. With twisted pair, the noise exposure is expected to be equal for both lines in order to cancel each […]
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This is a grid dip oscillator (GDO) circuit developed by Luigi Falcone. This circuit uses seven plug in coils covering 3.0 to 30Mhz. This circuit can be connected to the a frequency meter by using The coaxial socket J2. The figure below shows the schematic diagram of the circuit and the coil information: DC amplifier is formed by TR2 that […]
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This is a phone bug circuit. This wireless telephone line spy circuit can be used to transmit the phone conversation to a nearby FM radio. This circuit must connected to a normal phone line. Here is the schematic diagram of the circuit: The first transistor is turned off, if the voltage drops to less than 15v (if the telephone line […]
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Basically, this circuit is a radio frequency (RF) oscillator that operates around 100 MHz. The audio which is picked up and amplified by the electret microphone is fed into the audio amplifier stage built around the first transistor. Output from the collector is fed into the base of the second transistor. By varying the junction capacitance of the transistor, this […]
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