Simple Timer (MSB042E)

This circuit uses a capacitor to store energy. The capacitor is charged by closing S1 by a moment. Them, during the discharge across the transistor, it keep the LED on. After the discharge, the transistor turn off and also the LED. Figure below shows the basic circuit.










In the simulation the capacitor is reduced to make the process faster. You can alter this component to have other times.



Close by a moment S1 using the space key

When the key is open the LED remains on by a time interval given by C1.




To download the simulation files and Netlist - click here (

Circuit Bench