Roman numeral display (CB22160E)

This circuit shows numbers I II and III when mounted on its side, depending on the position of the selector switch.

Intercom LM388 (CB10936E)
This circuit was obtained in a 1991 Electronics Handbook. The publication no longer exists, but...
Integrated Microphone Amplifier LM383 (CB1345E)
This circuit makes use of an uncommon integrated circuit. It can provide a power of 6 W when...
Preamplifier Module (CB1386E)
This circuit of the 1970s uses Germanium transistors. Changes can be made to use silicon...