This circuit recognizes a tone determined by the tuned input circuit (R3 / R4 / C2). The circuit was found in Radio Electronics from the 90s. The 4046 is not a common component today.
Capacitor C and resistor R in this circuit determine the time the output remains at the high level...
This circuit for modeling was found in a 1980s documentation. The SCR can be the TIC106 and the...
To excite a higher power load, such as a 40mA lamp, we have the circuit in the figure. For this...