This static switch or electronic contactor was found in a 1968 Motorola publication. The triac depends on the current of the load it controls. The values shown are for the 120 V power grid.
This configuration with the LM383 appears elsewhere on this site. The circuit shown was obtained...
This signal attenuator was suggested by Electronics Now magazine in April 1999. The circuit is...
The voltage gain of this DC amplifier is 100 times, given by the relationship between R2 and R1....