This 1974 circuit uses two 555 integrated circuits in a very traditional configuration. The circuit can be powered by voltages from 9 to 12 V and for greater volume an amplifier stage can be added.
This simple teaching circuit uses 5 transistors in a monophonic organ version whose notes are...
We found this circuit in documentation from the 80s. The circuit is for cars with platinum. The...
This circuit for the medium wave range was published in Radio Electronics in February 1958. The...