Found in American documentation from the 90s, this circuit has the signal frequency determined by capacitors from C4, C3, C2 and C5 selected by digital switches.
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...