We found this circuit in a Popular Electronics from the 90s. Transistors can be modern equivalents. Observe the high supply voltage.
This is the old name given to flip-flops or biestable multivibrators. In fact, this is a 1967...
One of the problems with common multimeters, especially analog ones, is that their low resistance scales...
This simple circuit uses small speakers for both listening and speaking (microphone). The feeding is...