This circuit synchronized by the power grid can be used as a shield. We found it in an 80's Electronic Engineering. R1 can typically be 4k7.
Found in an EDN from the 90s, this circuit uses an electret microphone. The output can be used to...
This circuit is characterized by the configuration that accelerates the switching, being ideal for the...
This circuit makes use of a PLL 567 to invert the phase of a signal, ie to change it from 0 to 180...