Found in a 1968 EEE, this switch controls a high-power load from an audio signal. The current is determined by the type of SCR.
Found in a 90s 73 magazine, this circuit uses an unusual component today which is the XR2206. |...
This random noise or white noise generator was published in Radio Electronics magazine in July...
This circuit was found in Philips documentation from 1967. The phototransistor is from that time,...