Posted on Jul 16, 2012

This circuit is a bidirectional amplifier that can amplify both signals of a duplex telephone conversation. It uses the principle of negative resistance. Obviously, such an amplifier could easily be unstable; however, you can adjust Rl for maximum amplification and the circuit will remain stable.

Click here to download the full size of the above Circuit.

The LM324 op amps can be replaced with op amps that would distort less, such as the LM1558, LF412, LF353, or LF442.

Leave Comment

characters left:

New Circuits



Popular Circuits

Protection For Telephone Line Circuit
SMPS circuit
op amp square wave generator
digital room thermometer using lm35 sensor 8051 microcontroller
Schematic Diagram Anti Theft Car wireless alarm
Relay Coil Energy Saver
Voltage Controlled LFO
Demodulating Receiver
Switching the constant current source consisting of the application circuit W723
Practical digital amplifier TL084