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.
This circuit is based on an integrated TIPL62 from Texas Instruments, uncommon today and an...
This circuit appears in other articles and suggestions for circuits in this section from other...
This circuit was obtained from an Electronic Design from the 90's. The circuit generates signals at a...