We found this circuit in an Electronic Design from 1965. The 4-layer diode is an unusual component these days and can be used in its place with a diac.
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...