PC address decoder (CB20536E)

This TTL decoder circuit for PC ports was found in a document from 1992. The power supply can be PC's own circuit.

Full Wave Rectifier (CB5161E)
The DC output of this circuit corresponds to the RMS value of the input voltage. The circuit is...
Balanced Microphone Preamplifier I (CB4943E)
This circuit was obtained from an American publication of the 80's. The integrated circuit is of the...
Adapter for Multimeter (CB1360E )
If you have a common analog multimeter, you can increase its input resistance in the measurement of...