This old circuit, from the 80's, uses an integrated circuit that is uncommon today. The circuit is intended for loads controlled by triac and the resistors depend on the desired control.
Found in Motorola's 1968 documentation, this control appears elsewhere in this section. The bridge...
With this circuit, found in a 1978 publication, we can measure capacitances from 5 pF to 1 uF. The...
The Texas TL783 integrated circuit is a three-terminal high voltage regulator with a wide range of...