Power Supply Resumption Alarm

Summary of the circuit

Power Supply Resumption Alarm circuit will give you sound effects and visual effects at the time when power resumes.
The power fluctuations may damage your electronic devices like TV, Fridge, etc. For this we have used power stabilizers, but they are costly and power consuming too.
This circuit is less costly to construct also consumes less power.
This circuit needs only 9 V to work.

Principle behind Circuit

The circuit which is shown here is easy to configure. In this circuit IC1 is mounted in an unusual mode. When power resumes, pin 2 of IC1 which is connected through capacitor C1 is grounded and goes low while pin 3 of same IC switches to high. In turn pin 4 of IC1 which is a reset pin, switches to high state for approximately 10 seconds. When the voltage at C1 reaches to 2/3 of the supplied voltage, capacitor starts discharging and output switches to low, grounding the pin 4 which is a reset pin and hence the fallen circuit moves out of action.

Alarm circuit is made up with the help of second IC i.e. IC2. Astable mode of this IC is used in this circuit and the working frequency of the IC is 1 KHz. At the time when the output at IC1 is at high state, IC2 comes into action.

So the speaker will generate the alarm for approximately 10 seconds. After this time duration, IC1 switches back to its stable state. With the help of pin 7, capacitor C1 quickly discharges and for the circuit all set for the next recognition, as the pin2 of IC1 is at low state. So when the supply breaks off for the next time it will generate a sound. LED is used in the circuit to provide a visual effect.

Components required building the circuit

IC1,IC2 NE555

Resistor

R1 1M

R2 1K

R3 68K

R4 330K

Capacitor

C1 10uF

C2,C3 0.01uF

C4,C6 470uF

C5 100uF