This 1960s Signalite circuit uses two SCRs to achieve full wave control. The trigger elements are neon lamps.
Found in a European magazine from the 90s, this circuit emits beeps that are several seconds apart to...
The figure shows how to add a Darlington stage to an operational amplifier in order to obtain a...
This amplifier has a few Watt output, using old transistors. The speaker is 45 ohms, but with...