This commercial signal follower was found in a 1967 Japanese magazine. It uses germanium transistors and provides a speaker output without the need for a transformer.
This sonic, sound or vox switch uses common SCR and transistors can be BC548 or equivalent. The...
This circuit allows you to use a calculator as a timer by directly activating a sum key with...
This circuit is from the time when photos were revealed in darkrooms. We found it in a 1968...