This circuit was obtained from a 1967 GE SCR manual. It is intended for controlling relays responding to a decrease or increase in temperature.
This circuit is from an American publication from 1970. It uses a coal microphone, which is...
This unijunction transistor flasher or blinker was found in an old Popular Electronics. The...
This Linear Technology circuit was found in a 1980s documentation. The circuit can swing up to a...