This circuit was obtained in a 1978 publication. The supply can be symmetrical from other voltages. Frequency can be changed by changing the capacitors.
This circuit was found in the April 1968 Radio Electronics magazine. The circuit uses two FETs...
Found in an EDN from the 1980s, this circuit uses a double 555. The circuit activates a relay that...
Found in an old Popular Electronics this circuit appears in other variations on this site and in...