Solid state relay (CB8518E)

This circuit was found in a 90s Popular Electronics. Both the coupler and the MOSFET can be of any type.

Low Consumption Pulsator (CB20346E)
This circuit produces the ticking of a clock on a common piezoelectric transducer. The circuit has an...
Band Pass Filter 741 (CB16220E)
The basis of this circuit is a double T in the feedback, which has the components calculated to...
Phototransistor Optical Ttrigger (CB14648E)
This configuration was found in the Texas Instruments optoelectronics manual. PNP transistors...