This power saving circuit is used to save electricity while ironing. The circuit will switch OFF the iron box when it is not in use. Once the ON time of the circuit is crossed, it will produce an alarm. If we press the Reset button at the time of alarm it will turned OFF the alarm and extend the ON time of the circuit to the next 4 minutes. This circuit will work as a reminder for those who always forget to turn OFF the iron box in this day to day busy life.
In this circuit is build around NE 555(IC1), op-amp LM 358 (IC2) and few components. IC1 is designed as a standard monostable multivibrator and its trigger pin 2 is held high by resistor R1.LM 358 is configured as a comparator. Its non-inverting input (pin 3) and the inverting input (pin 2). Inverting pin 2 of IC2 is connected to voltage-divider preset VR1. Using preset VR1 we can vary the reference voltage at pin 2. Buzzer is connected to the output pin 1. Initially output pin 1 of IC2 is low.
Fig. 1: Prototype of 555 IC based Iron Box Power Saver Circuit