LED Brightness Controller Circuit - JLCPCB

A common brightness-control circuit for LEDs uses an electrically controlled potentiometer (EPOT) to achieve digital control of the LED brightness. There is an alternative that reduces the number of ICs and control lines. You can control each LED driver directly with a single output port.

Once the power is in the correct direction to flow through the LED, the brightness is determined by the current, or the speed of the flow of power. The more electrons filling holes, the more photons released, and the higher the brightness output.

It's the forward current that determines the brightness of an LED, not the voltage. In the case of an LED current vs luminous intensity is pretty linear, that is to say 2x the current 2x the brightness. If you want to control the brightness of a LED, you need to control the current flowing through it.

The final circuit diagram and design can be seen above. We also thanks to our sponsor JLCPCB https://jlcpcb.com/RTA for sponsoring us PCB for this project.

The article is being published in collaboration with JLCPCB. They supply high quality PCBs at a very reasonable price. They also can provide SMT circuit assembly.

The final circuit diagram and design can be seen above. We also thank to our sponsor JLCPCB https://jlcpcb.com/RTA for sponsoring us PCB for this project.

Thanks to JLCPCB.

$2 for 1-4 layer PCBs.

Get SMT Coupons - https://jlcpcb.com/RTA

To make this LED brightness controller circuit, the circuit can be enclosed in a small plastic or metal casing with a switch to turn it on and off. A small keychain or lanyard can also be attached to the casing to make it easy to carry around.

Additional components, such as capacitors, resistors, filament bulb or transistors, can be added to the circuit to control the brightness or flashing pattern of the filament bulb.

All component lists have to been given below.

Component list -

1. PCB by JLCPCB

2. Transistor - BC 547

3. Capacitor - 47µf/ 25v

4. Resistor - 1 MΩ, 1 KΩ, 2.2 KΩ, 4.7 KΩ*2 and 220 Ω

5. Volume - B 100K

6. LED

8. Power Source - DC 12v

The BC547 is widely used general-purpose NPN bipolar junction transistor.

1.      Suitable for use in low-noise amplification circuit

2.      DC current gain ranging from 110 to 800

3.      Low voltage drop, typically around 0.7v

4.      Maximum collector current rating of 100mA

5.      Maximum collector-emitter voltage rating of 45V

6.      BC547 is also available in TO-92, SOT-23 and SOT-223 package.

The pin arrangement may vary depending on the manufacturer or package type, but the pin functions remain the same.

1.      Collector

2.      Base

3.      Emitter

The schematic of LED brightness controller circuit along with the PCB layout can be seen above.

Since it is a 12v LED light project circuit, for that we need to use DC-12v led light. Though we are using 3v led light, for that we need to convert 3v led light to 12v led light.

We use 4 pieces 3v LED light to make a 12v LED light. We connect one LED positive leg with another LED negative leg. In this way we will leg a 12v LED light.

This way, we might make 2 pieces 12v LED light. Then we connect 2 pieces 12v LED light negative leg with each other.

To make this circuit 1st we connect 4.7 KΩ resistor with 12v led light. We make series connection between these two resistors. Then connect two resistors two empty terminal with 12v LED light negative terminal.

Again we make a series connection between 1 MΩ and 2.2 KΩ resistors. Then connect these two resistors with BC-547 transistor. We connect 1 MΩ resistor with "Base" leg of transistor and connect 2.2KΩ resistor with "Collector" leg of BC-547 transistor.

We also connect LED positive terminal with series connection of resistor and connect another positive terminal with "Emitter" leg of transistor.

Now we need to connect capacitor with the circuit. We make series connection in these three capacitors. In these three capacitors, we will get only one positive terminal and one negative terminal. We connect capacitor negative terminal with "Base" leg of transistor and connect capacitor positive leg with "Collector" leg of transistor.

To control brightness, now we need to connect volume with the circuit. We Connect volume ground leg with capacitor negative leg and connect volume output leg with "Emitter" leg of BC-547 transistor.

For power source we are using 12v battery or 12v adapter. We connect DC-12v negative cable with "Emitter" leg of transistor and connect DC-12v positive cable with the series connection of 1 MΩ and 2.2kΩ resistor.

Neat and perfect soldering is an important part for all kind of PCBs. Since soldering, you should remember that, there should not be any kind of short circuit connection. After soldering all leg, we cut-off the extra leg of all electronics component.

We also can use liquid PCB cleaner to clean the PCB board.

Our circuit is completely ready for use now. We need to power switch ON and put audio source beside MIC. Then play music and enjoy the awesome effect of filament bulb.

Again thanks to JLCPCB for best quality PCBs.

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Thanks to JLCPCB for best quality PCBs.