This circuit was obtained in a QST magazine from the 90s. The circuit makes use of components that are uncommon today. The circuit includes a gain selection switch.
This very high input impedance circuit is suggested by Texas Instruments. The circuit can be...
Found in Unitrode documentation, this oscillator uses some unusual components today such as PU and...
Other operational amplifiers in the series, such as the MC34072, MC34074, MC35071, MC35072,...