This tone control was obtained in a Signetics documentation of the 90s. The integrated circuit can be practically any operational amplifier. The power supply is symmetrical.
This circuit was found in an English documentation from the 90's. Equivalent components such as...
This circuit was found in an Electronics Now of the 80s applying to NiCad batteries of the time....
The pulses applied to input C of the SAA1027 integrated circuit determine the engine speed. Each...