Two-channel peak indicator (CB21975E)

This peak indicator for stereo amplifiers uses a CA3130. The 80's circuit does not need a symmetrical power supply.

Simple Alarm with SCR (CB24114E)
Found elsewhere in this section, this circuit is from the April 1971 Radio Electronics magazine. Note...
Relay Drive AC Stage (CB12182E)
With this circuit, a relay can be activated from an alternating signal with frequency up to a few...
Theremin Optical (CB14988E)
The sound of this experimental musical instrument is produced by the movement of the hand in front...