Automatic Dimmer Dipper Circuit for Automobiles is a simple and small electric device for vehicle.
It is used for change headlight brightness by itself when other vehicle come from front.
Because too much light can make other driver blind at night, this can make an accident.
So main purpose is make driving more safe.
When no vehicle come from front circuit changes high beam back to low beam and it does this automatic after it sees other car light.
This device help make driving more easy and safe and also helps driver not to feel sleepy.
WARNING: Making car circuit is not safe.
Do only this only when adult and mechanic fixes it in car.
What is a Automatic Dimmer Dipper for Automobiles:
Car headlight control is also called as dipper or dimmer sometimes.
It is having two setting which we can choose:
High beam is very bright and is good for night time seeing.
Low beam is used for normal driving so it does not blind other drivers.
Even if name say “automatic dimmer dipper” it not always it changes light by itself.
Many new car have smart system but when it see other car light it changes high beam to low beam automatic.
This system is called automatic high beam control or something like that.
Why Automatic Headlamp Dimmer Dipper is Important:
At night driving is hard because bright light from other car make problem for eyes.
Manual dipper switch is not easy because driver needs to use it again and again which is very hard when there is stress or traffic.
So automatic headlamp dimmer dipper system is important which helps stop accidents and keep both drivers safe.
This circuit do dimming work by itself and makes driving easy on busy road with no need to worry.
Circuit Working:

Parts List:
Category | Description | Quantity |
---|---|---|
Resistor | ||
1k 1/4 watt | 1 | |
Light Dependent Resistor any standard type | 1 | |
Preset 10k | 1 | |
Semiconductors | ||
Transistor BC547 | 1 | |
Diode 1N4007 | 1 | |
Relay DPDT 12V | 1 | |
Automobile Bulbs High Beam and Low Beam | 2 |
Main part of this circuit is transistor which works like comparator.
It checks LDR resistance and compare with fixed resistance.
LDR is put on car glass at windshield facing front so it can see light from other cars.
When other car headlight hit the LDR its resistance goes down fast.
Then more current goes to transistor base.
Because of this transistor turn ON.
DPDT relay is connected to transistor base, emitter and collector and when transistor is ON the relay also turns ON.
Relay then switches the headlight to dipper filament.
So when other car come headlight become dim automatic.
DPDT relay help to stop sudden flicker or cut it makes smooth change in headlight.
All parts like transistor, LDR, relay and circuit are put inside small box.
This box is kept near driver easy to reach.
LDR must be outside the box so it can see light from front cars.
This help it to change light in right time.
Formulas:
Below is the formula for Automatic Dimmer Dipper Circuit for Automobiles:
Voltage Divider:
Voltage divider circuit is used to change how sensitive the LDR is and sometimes this is not shown in diagram.
It uses two resistors R1 and R2.
These resistors connect in series and the output voltage come from point between them.
Formula for output voltage (Vo) is:
Vo = (R2 / (R1 + R2)) × Vin
where:
- Vo is the Output voltage
- R1 is the first resistor
- R2 is the second resistor
- Vin is the input voltage
By changing R1 and R2 value we can control how LDR works.
When voltage goes low LDR become more sensitive to light.
How To Build:
Below are the constructions steps for Automatic Dimmer Dipper Circuit for Automobiles:
Circuit Assembly:
- First connect LDR with transistor to make voltage divider.
- Then connect DPDT relay to transistors collector, emitter and base.
- Set fixed resistance to compare with LDR resistance.
Relay Connection:
- Connect relay to cars headlamp wire.
- Use DPDT relay so headlight not flicker or loses brightness.
LDR Connection:
- Fix LDR on windshield facing road.
- LDR must see coming vehicle light clearly to work good.
Enclosure Installation:
- Put all circuit parts in small box near driver dashboard.
- LDR should stay outside box so it can see light from other cars.
Conclusion:
This Automatic Dimmer Dipper Circuit help make car more safe.
It help driver by changing headlight brightness when other car is coming at night where there is no need to do it by hand.
To uses this smart technique which is installed carefully with help from a expert or mechanic.
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