This circuit is from a 1968 Electronic Design. The circuit uses transistors of the time that can be replaced with modern equivalents. More stages can be used to get higher tension.
In the figure we have the way to implement a NO OR or NOR gate with an operational amplifier. The...
Old phones with dials can be used in a simple home intercom system, as this circuit from Popular...
The pulses applied to input C of the SAA1027 integrated circuit determine the engine speed. Each...