The figure shows how to use an operational circuit as a voltage divider. The circuit is from a Radio Electronics magazine from June 1986. The reference voltage is given by a zener diode.
This protection circuit for symmetrical 28 V power sources was found in a 1968 EEE documentation. The...
This Japanese commercial medium and short-wave radio uses 7 transistors and tunes the range from...
An application for the previous circuit (CB109) is shown here. The central frequency is determined by C and...