The operational amplifier used in this application is uncommon today. This Raytheon circuit can be designed with equivalent operational and the power supply must be symmetrical.
Found in Unitrode documentation from the 1980s, this circuit makes use of PUTs, currently common...
This circuit uses a PUT, a component not very common nowadays. Its purpose is to provide an...
Using 4 operational amplifiers this circuit generates 4 different tones. The circuit is from an...