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.
This circuit is from 2001 documentation and consists of a small FM transmitter with two inputs, one...
This amplifier, of excellent quality, provides a power of 40 W IHF, or 22 W RMS, in a load of 8...
The input of this regulator can be between 7 and 12 V and the output is 5 V. The circuit is from...