Microammeter (T465E)

Found in a 1948 MIT documentation, this circuit uses a 0 to 100 uA microammeter as an indicator. The power supply is 150 V.

American Siren (CB12204E)
We found this version of the siren that makes the American police siren sound in a 1980...
Transformerless Balanced Preamplifier (CB4942E)
This microphone circuit was found in a collection of American 80's layouts, using operational...
Rumble Sub Sonic Filter (CB15209E)
The integrated circuit used in this filter is like to a double 741 and must be powered by a...