With this circuit it is possible to use a pair of old telephones in a wired communication system. The circuit is from a Popular Electronics from the 90s.
This CMOS Flasher was found in a Popular Electronics from 1978. It can still be easily assembled, as all...
In the figure we have the suggestion of coupling an audio oscillator to monitor the CW...
This double bench source has a fixed voltage output and an adjustable voltage output with current up...