This TTL shield with high level logic is from the LM111's own 80's manual. The integrated circuit is no longer easily found, but the circuit can be adapted to use modern equivalent operational amplifiers.
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...