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How to Make Car LED Bulb Circuit

Last Updated on December 8, 2019 by Swagatam 8 Comments

Typically all car turn signal lamps are around 12 to 20 watt rated which are traditionally incandescent bulb types and produce much lower light intensities compared to LED lights. Here I have explained how these lamps can be replaced with high efficiency, high intensity car LED bulbs.

Table of Contents
  • LED Car Bulb Design
  • Technical Specifications of the 3020 LEDs are:
  • Construction
  • Circuit Diagram

LED Car Bulb Design

The image below shows what could be a car LED lamp directly replaceable over the existing holder.

It shows a decent looking arrangement of flat, tiny SMD LEds in a circular pattern for enabling optimal distribution of light via the enclosed hind reflector.

The LED used here are the 3020 SMD LEDs, these tiny light emitting diodes are identical to the ordinary 5mm LEDs with their specs, however if we compare their light intensities, the witnessed difference appears to be huge, where the 3020 easily wins by an outstanding margin, that's why these LEDs are much preferred in place of the ordinary 5mm LEds nowadays.

Technical Specifications of the 3020 LEDs are:

  • Forward voltage: 3 to 3.2V
  • Forward current: 30mA optimal
  • Luminous Efficiency: 100-110lm/w
  • Size: 3.0x2.0x1.3mm
  • Lifetime: 50,000hrs
Making car LED bulb circuit using SMD LEDs

Construction

In the above image, we can see the LEDs assembled over pcs of PCB strips, tiled in a particular calculated manner.

The vertical PCBs are 7 in numbers, and have 4 LEDs on each strips.

One circular PCB consisting of 22 LEDs can be seen positioned over the vertical PCB structure.

The vertical PCBs thus include 7 x 4 = 28 nos of 3020 LEDs, while the circular PCB mount 22 nos of LEds, giving a total of 28 + 22 = 50 LEDs

These 50 LEDs are connected to form 12 strings of 4 LEDs each, and a single string of 2 LEds.

Each of the 12 strings must have their own individual series resistor (SMD) whose value could be around 55 ohms 1/4 watt.

The single 2 LED string must associate a separate 250 ohm, 1/4 watt resistor.

These resistors act like current limiters for safeguarding the LEds from car alternator voltage fluctuations and also help to keep the illumination level across all the LED groups as uniform as possible.

The resistors can be installed at the rear side of the PCB strips.

The circuit diagram for the proposed simple car LED lamp is shown below:

Circuit Diagram

simple car LED bulb circuit using 3020 SMD LEDs

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Filed Under: Automobile Electronics, Lamps and Lights Tagged With: Bulb, LED

About Swagatam

I am an electronics engineer and doing practical hands-on work from more than 15 years now. Building real circuits, testing them and also making PCB layouts by myself. I really love doing all these things like inventing something new, designing electronics and also helping other people like hobby guys who want to make their own cool circuits at home.

And that is the main reason why I started this website homemade-circuits.com, to share different types of circuit ideas..

If you are having any kind of doubt or question related to circuits then just write down your question in the comment box below, I am like always checking, so I guarantee I will reply you for sure!

Previous Post: « Simple Automatic Plant Watering Circuit for Monitoring Soil Moisture
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Reader Interactions

Comments

  1. Safak TASKIN says

    July 5, 2024 at 7:28 pm

    Hello. When operating voltage is applied to LEDs, they tend to draw insatiable current. (Avalanche current) To limit this and provide the desired operating voltage, series resistors are connected.

    Reply
  2. Abdul Basit Momin says

    October 22, 2019 at 12:45 am

    How can we make 50 led string in series of this bulbs

    Reply
    • Swagatam says

      October 22, 2019 at 10:16 am

      Make 16 strings having 3 series LEDs with a calculated resistor. Then connect all the strings in parallel with 12V supply

      Reply
      • Abdul Basit Momin says

        October 23, 2019 at 10:52 am

        And how will the circuit for 230v

        Reply
        • Swagatam says

          October 23, 2019 at 2:15 pm

          for 230V connect all of them in series and use the first circuit from this article to control it

          https://www.homemade-circuits.com/how-to-make-led-bulb-circuit/

          Reply
  3. satheesh k Nalluswamy says

    May 3, 2016 at 9:48 am

    Thanks for your help

    Reply
  4. satheesh k Nalluswamy says

    May 2, 2016 at 1:40 pm

    Dear sir,
    please provide above the led resister calculation

    Reply
    • Swagatam says

      May 3, 2016 at 3:35 am

      Dear Satheesh, you can use the following calculator for knowing the results:

      https://www.homemade-circuits.com/p/led-resistor-calculator_21.html

      Reply

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