We found this circuit in an old documentation, but it is still current. General purpose transistors can be used, and the SCR can be the TIC106. The bell is a transducer with an oscillator (buzzer).
To increase the control capacity of the CA3140, an amplifier circuit can be used, as shown in the...
The figure shows a simple circuit to power LEDs from the AC Power Line. The resistor can be a wire...
This circuit was found in documentation from the 1980s. Transistors are general-purpose types like...