This circuit allows the listening of undersea sounds using a special transducer. Operational amplifiers can be of any type. The circuit was found in a Popular Electronics from the 90s.
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...