Published in a February 1978 Radio Electronics magazine article, this digital circuit uses some of the integrated circuits of the time. The circuit uses a LED bargraph.
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...