This circuit was found in the February 1970 issue of Radio Electronics magazine. The integrated circuit is a type of the time. It consists of a high-gain differential amplifier.
This circuit using an operational amplifier was found in old American documentation. It can be...
If the circuit oscillates, emitting sound, it is because the transistor is good. This simple...
Like the previous circuit, this is used in the analog part of the telephone lines. The same...