Found in an old Popular Electronics this circuit can also be adapted to be used as a shield. In this version the control can trigger loads from the light that falls on an LDR.
This circuit produces the ticking of a clock on a common piezoelectric transducer. The circuit has an...
The basis of this circuit is a double T in the feedback, which has the components calculated to...
This configuration was found in the Texas Instruments optoelectronics manual. PNP transistors...