This simple timer can be used in many applications such as egg timer. The LED glows up when S1 is closed by a moment remaining on by a time interval that depends on C1 and R2/R3; Time up to some minutes can be reached with larger capacitors. Values up to 1,000 µF can be used. The circuit can be powered from 5 to 12 V supplies.
To download the simulation files and Netlist - click here (msb0123.zip)