This circuit was found in a 1980s documentation. Similar configurations appear in the section, but from different sources. The circuit makes use of components of the time.
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...