A Power failure emergency lamp is a common electronic device, usually served in day-to-day households. They provide an easy and inexpensive way to obtain emergency light in case of a power/grid failure. So, in this project, we are going to build a simple Power Failure Emergency Lamp Circuit using PNP transistors.
Emergency Lighting operates in the event of a complete mains power failure, in order to prevent panic and allow safe passage out of enclosed areas in the event of an emergency situation such as fires, flash floods, and wide-scale road accidents. Like all other forms of artificial lighting, Emergency Lighting is provided by luminaries. Luminaries come in many types such as LEDs, incandescent bulbs, etc, each type designed to fulfill specific requirements.
Hardware Components
The following components are required to make Power Failure Emergency Lamp Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | PNP Transistor | BD140 | 1 |
| 2. | Transistor | 2N3906 | 1 |
| 3. | Resistors | 51K/1W, 22K, 10 Ohms/1W | 1 |
| 4. | Diode | 1N4007 | 1 |
| 5. | Capacitor | 10uF | 1 |
| 6. | Breadboard | – | 1 |
| 7. | Connecting Wires | – | – |
| 8. | LED | 1W | 1 |
| 9. | Battery | 4.5V | 1 |
2N3906 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N3906
BD140 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of BD140
Power Failure Emergency Lamp Circuit
Working Explanation
The working of this circuit relies on the operation of two PNP transistors. When power is applied to the circuit the first transistor Q1 turns ON and Q2 turns off. When the mains supply goes off for any reason then the transistor Q1 will go into the off state due to which the Q2 will turn ON and activates the 1 watt LED
The three 1.5V batteries act as backup power to operate the 1-watt LED. Any type of three 1.5V batteries like AA or AAA size can work for this purpose.
Applications
- Serves as an emergency backup in security systems and industrial sites.
- It can function as an emergency lamp in home & office setups.
- It can serve in study rooms and workplaces in order to avoid sudden power failures.
