This circuit generates quadrature signals, that is, with a 90-degree phase difference. The circuit must be powered by a symmetrical source and the frequency depends on the capacitors.
This circuit was found in a 1992 publication, using an operational amplifier not very common...
This is a amplifier for XTAL high impedance earphones or piezoelectric types. Current drain is...
This circuit is from the LM111 manual of the 1980s. The component no longer exists, but...