Found in 90s Popular Electronics, this circuit produces a modulated infrared beam for a remote phone whose circuit is shown right after it. Infrared LEDs are common.
This switched stepdown regulator was found in a 60s documentation. It makes use of unusual...
We found this active crossover in a Radio Electronics magazine from June 1961. Note the different...
This spot gun or spotlight for cars with a distributor (old models) was found in a publication from the...