This circuit makes use of a low impedance microphone. The relay is according to the supply voltage which can be between 9 and 15 V. The operational gain is approximately 100.
We found this circuit in a publication from the 1970s. The circuit has a logarithmic gain...
Atmel's ATmega 324PB microcontrollers available from Mouser Electronics are RISC-based...
The purpose of this circuit is to provide the distribution of analog video signals between several...