Found in Precision Monolithics documentation from the 90's, this circuit equalizes octave signals determined by the capacitor values according to the table next to the diagram.
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...