In this tutorial, we are going to make a “Main Power Interruption Alarm”. A power supply interruption alarm is a circuit that prevents a fault in the event of a commercial power supply interruption or a power supply voltage drop caused by an accident that can affect units that are connected to the same power source. Hence, the circuit uses a buzzer or any other component that notifies the interruption happens,
This main power interruption alarm circuit is made up of just a few simple components including, a transformer, diodes, and transistors. All components are easily available which makes this circuit more convenient to make.
Hardware Components
The following components are required to make Main Power Alarm Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Transistor | BC547 | 1 |
| 2. | Step down Transformer | 9v | 1 |
| 3. | Diode | 1N4007 | 2 |
| 4. | Buzzer | – | 1 |
| 5. | Electrolysis Capacitor | 2200uF, 10uF | 2,1 |
| 6. | Resistor | 22KΩ, 33Ω | 1,1 |
| 7. | 2-Pin Connector | – | 1 |
BC547 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of BC547
Main Power Alarm Circuit
Working Explanation
In this Main Power Interruption Alarm, we are using an AC supply of 230V. Therefore, to step down the voltage we have used the step-down transformer which transforms 230V AV into 9V AC. rectified by the half-wave ( made up of two diodes) rectifier, and after that, this rectified DC voltage is given to transistors Q1 and Q2, which operate are working as a switch to separate the buzzer from the power source when the main power supply is present.
Now, if the main power supply is disrupted, the Q2 transistor and buzzer get sufficient power through the capacitors C2 and C3, and the buzzer produces a beep sound while the capacitors C2 and C3 are charged.
If the power supply is linked to the ground through Q1, the Q2 transistor base is connected to the ground, and the Q2 transistor is open, resulting in no buzzer sound.
Application and Uses
- This circuit is useful to monitor the main power supply.
