We found this circuit in the April 1978 issue of Radio Electronics magazine. The power supply must be symmetrical, and the maximum recommended frequency is around 10MHz.
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...