This circuit uses an HA2400 consisting of 4 digitally controlled operational amplifiers. The circuit is from a Radio Electronics magazine from March 1980. The power supply must be symmetrical.
This original 70s RCA circuit appears elsewhere on this site, including original RCA...
This circuit, which makes an astable multivibrator, was found in the March 1973 issue of Radio...
This circuit uses two unijunction transistors and only one capacitor, generating signals at a...