Found in an Electronic Design and 1970s, this circuit uses transistors of the time. The transistors can be replaced with equivalents and the relay is 12 V depending on the power supply.
This circuit allows to increase the output power of a 741 as an amplifier. The circuit is from a...
This high voltage circuit was found in a 2005 Linear Technology application manual. The circuit...
This circuit for multiple sound inputs was found in a Radio Electronics from January 1992. It...