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.
We found this circuit in Motorola's Linear Databook in 1990. The integrated circuit used is no...
This circuit emits an alert sound (interval beeps) if the car lights are left on and the ignition key...
This oscillator produces a signal with a central frequency in 1 MHz. This frequency can be...