This energy saving circuit is used to save electricity during ironing. The circuit will turn off the iron box when it is not in use. As soon as the circuit's ON time is exceeded, it will produce an alarm. If we press the Reset button at the time of the alarm, it will turn off the alarm and extend the circuit on time to the next 4 minutes. This circuit will act as a reminder for those who always forget to turn off the iron box in their busy daily lives.
This circuit is built around NE 555 (IC1), operational amplifier LM 358 (IC2) and some 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 inverting input (pin 2). Inverting pin 2 of IC2 is connected to voltage divider preset VR1. Using the preset VR1, we can vary the reference voltage at pin 2. The buzzer is connected to output pin 1. Initially, output pin 1 of IC2 is low.
This energy saving circuit is used to save electricity during ironing by turning off the iron box when it is not in use. Once the circuit activation time has passed, it produces an alarm. If we press the reset button at the time of the alarm, it is turned off and the circuit's on time is extended to the next 4 minutes. This circuit works as a reminder for those who always forget to turn off the iron box in their busy schedule.
In this, the circuit is built around the NE 555 (IC1), the LM 358 operational amplifier (IC2) and some other components. IC1 is designed as a standard monostable multivibrator and its trigger pin 2, held high by resistor R1.LM 358, is configured as a comparator. It has a non-inverting input (pin 3) and an inverting input (pin 2). The inverting pin 2 of IC2 is connected to the preset voltage divider VR1, which helps in varying the reference voltage at pin 2. The buzzer is connected to the output pin 1, which is initially low.
The 'ON' time of IC1 is adjusted to 4 minutes with the help of capacitor C1 and resistor R1. Output pin 3 is fed to the relay driver transistor.
548 BC.
When key S1 is pressed, the monostable (IC1) is activated, the output of IC1 becomes high and the iron box is turned on through relay RL1. LED2 (yellow) is used to indicate that the output is on.
Under normal conditions, the voltage at the non-inverting pin of the LM358 (IC1) is lower than the voltage at the inverting input of the LM358, and therefore the output of the op amp is low.
The timing capacitor C1 begins to charge and the voltage at the LM358's non-inverting pin (IC1) becomes greater than the voltage at the LM358's inverting input. Therefore, the output of the op amp is changed to high. This, in turn, activates the buzzer, thus producing an audible signal. If we press the reset button S2 at the time of the alarm, it turns off the alarm and extends the circuit on time to the next 4 minutes. If the reset button is not pressed at the time of the alarm, the iron box will automatically shut down.
Assemble the circuit on a general-purpose printed circuit board and place it in a suitable enclosure. Mount the switches S1, S2 and the buzzer on the front panel of the box.
LIST OF COMPONENTS
