This circuit produces sounds of 6 different notes depending on the keys activated. The circuit is from a Radio Electronics from May 1965. The transistor must be equipped with a heat radiator.
This oscillator, from an old Argentine publication from 1973, uses the inductance of the 500 ohms...
Found in Popular Elecronics, this configuration also appears in this section, but obtained from other...
The operational ones used in this project are old types from National Semiconductor, since the...