This amplifier with fixed AC bias was found in a 1947 documentation. The circuit uses two transformers in the power supply and two full-wave rectifier tubes.
This Schmitt optical trigger with LDR was found in old documentation. The relay must be sensitive, or an...
We found this circuit in the January 1997 Electronics Now magazine. The triac determines the...
This transmitter uses a small loudespeaker (FTE) as microphone and can send the signals to...