Found in the December 1986 issue of Radio Electronics magazine, this circuit is designed to select 4 outputs with pulses from a pressure switch. The circuit includes LED indication.
We can implement this filter with more modern equivalent operational amplifiers, since the LM110 is...
This stethoscope or amplifier for hearing aid using a crystal headset and microphone was found in a...
The normal use of a 4520 as a divide-by-16 counter is shown in Figure bellow. In the normal...