This CMNOS crystal-based circuit generates a 2 Hz signal. It was found in the October 1994 issue of Electronics Now. The output signal is square.
This circuit works only with carbon microphones, due its low impedance. The speaker should be good or...
The integrated circuit used in this regulator is not very common today. The circuit is from old...
This is a typical point scale or moving bar circuit with the LM3915. We found it in old American...