This circuit is indicated for the application that the motor must not simply rotate but give a small boost to some devices by touching a pressure switch. As the figure shows, we have a high value capacitor connected in parallel with the DC motor. When we press the pressure switch, the capacitor charges and then discharges through the motor, keeping it running for a few seconds, depending on its current. Instead of S1 as a common pressure switch, sensors such as relays, reed-switches, micro-switches, and other devices that produce short pulses of current can be used.
