Found in a 90s Popular Electronics, this touch switch uses a single sensor. PLLs are common today. Observe the supply voltage range.
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...