Suggested by a 90’s Radio Electronics, this circuit automatically activates the recording switch of an old tape recorder. It can be adapted for other purposes.
This circuit uses a 555 (according to the diagram) to generate 50 ms tone bursts at a frequency of 1.5...
This circuit, suggested by Signetics can be used as a shield. Modern operational can be employed...
This circuit produces two signals with inverted phases. One is taken for the emitter of Q1 and the...