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, from a publication from the 1970s, can be implemented with more modern transistors and 6 or...
This plug-in control was found in General Electric documentation from the 1970s. The SCR can be...
This circuit is of an old Argentine magazine of the 70's. The difficulty for its assembly is in...