The idea of this circuit is that when the device in SO1 is turned on, the device connected to SO2 automatically receives power. The circuit is from Radio Electronics from January 1985.
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...