Like our previous tutorial on emergency light circuit, here is another post on 220V Emergency Light Circuit without Transformer.
Today, power cut is common problem, so emergency light is very useful, as it gives light when mains supply is OFF.
Usually, emergency light uses transformer but transformers are costly and bulky, therefore, this circuit is different, as it works without a transformer.
In this circuit, we have used direct AC supply, then we convert and control it carefully, also battery is used for backup.
So this circuit is simple with low cost and useful for home use.
Circuit Working:
Parts List:
| Components | Values | Quantity |
|---|---|---|
| Resistors (All resistors are 1/4 watt) | 220k, 33k, 10k, 1k, 15k | 1 each |
| Capacitor | Electrolytic 47uF 50V | 1 |
| Semiconductors | Transistor BC547 | 2 |
| Transistor BC337 | 1 | |
| Rectifier diode 1N4004 400V | 1 | |
| Switching diode 1N4148 75V | 1 | |
| Slider Switch | 1 | |
| Lamp 2.4V 5W | 1 | |
| Neon Lamp for Indicator | 1 | |
| Battery 3V | 1 | |
| AC Input 220V 50Hz | 1 |
First, AC 220V supply is given to circuit, then resistor R2 and diode D1 reduce and control current.
Next, neon lamp is used which indicates presence of AC supply and also, it helps in voltage drop.
After that capacitor C1 charges slowly, meanwhile, resistor R1 and R3 control charging speed.
When AC is present, battery charging path is active, so battery gets charged through diode D2.
At the same time transistor section remains OFF and therefore, lamp is OFF.
Now when power fails the condition changes, AC supply becomes zero, so neon lamp turns OFF.
Then capacitor discharges and after that a transistor Q1 gets bias.
Because of this Q2 and Q3 turn ON, now current flows from battery and finally lamp glows and thus, emergency light turns ON automatically.
Warning:
This circuit uses 220V AC, which is very dangerous as it can give electric shock.
Do not touch when power is ON, no transformer is used, so there is no isolation from mains.
Always switch OFF before working and use proper insulation.
If possible always use fuse in input line, as it gives extra safety.
Keep away from children, moisture and water.
How to Build:
To build a 220V Emergency Light Circuit without Transformer following are the steps one needs to follow:
- Start, the circuit by collecting all the circuit parts as in diagram above.
- First, connect 220V AC input to the circuit, in which one line goes through resistor R2 and then it connects to diode D1 and other AC line goes to circuit ground line.
- Next, diode D1 converts AC to pulsating DC, after that the current passes through resistor R1 and this limits the current.
- Then connect neon lamp L1 across the AC line which shows power ON condition.
- Now capacitor C1 is connected after diode, with positive side goes to supply line and negative goes to ground.
- After that connect a slider switch in series.
- Then connect diode D2 for battery charging, as its anode goes to supply line and cathode goes to battery positive.
- Battery negative is connected to ground.
- Now we will start with Q1 transistor emitter pin goes to ground, base pin is connected through resistor R4, and collector is connected to base of Q2.
- After that start with transistor Q2 emitter pin goes to base of transistor Q3, base pin goes to collector of Q1 and resistor R5 one end and collector pin is connected to lamp L2 one end.
- Then take transistor Q3 with emitter pin connect to ground, base pin goes to emitter pin of transistor Q2, and collector pin goes to collector of Q2 and lamp L2 one end.
- Finally, other terminal of lamp L2 goes to battery positive.
Conclusion:
This 220V Emergency Light Circuit without Transformer is very simple as it is with low cost and it does not uses a transformer, therefore, size is small.
However, it works directly on AC, so handle it with care.
It is good for learning purpose, also is useful for small emergency lighting and finally, this circuit is best for basic DIY electronics projects.