The frequency of each note depends on R2, which must be replaced by a keyboard. The circuit is from Radio Electronics from April 1980. The power supply is 9 V for the amplifier used.
The TAA865 integrated circuit used in this 1986 project is no longer common today. The circuit is a...
) These two circuits were obtained in a 1977 Radio Handbook. The transistors are from that time,...
The circuit shown is from the Motorola Linear Databook of 1990. It is based on the Motorola T...