LED Circuit

I have an inspection light that has several LED's in a 36" tube for inspecting inside cylinders. It works off a 12 V transformer. The light quit on me and when I opened it up there was a diode like component that was burned to a crisp in line with the LEDs. When I by-passed the burnt component the lights worked but flash on and off. Could someone tell me what the component is and where to buy a replacement?

by master302
April 21, 2018
Add comment...

Please sign in or create an account to comment.


2 Answers

Answer by mikerogerswsm

It may be a diode, for example a 1N4001 type, but you need to give more information, for example are the LEDs in series and what do you mean by 'flash'. It would be helpful if you could measure the input voltage and indicate the frequency, if any. mike

+1 vote
by mikerogerswsm
April 22, 2018

One amateur source is Mouser. Another is Farnell.

by mikerogerswsm
April 22, 2018
Add comment...

Please sign in or create an account to comment.


Answer by master302

The voltage is 12 V DC going into 12 LEDs wired in parallel. The diode like component is in series with the plus side before the LEDs. When by passed with a jumper wire the LEDs light up and flash on and off at about 1 sec. intervals. No components have any markings on them. The LEDs are bright white light.

+1 vote
by master302
April 22, 2018

Something strange here. The LEDs should take about 20mA each, so a dozen take only 250mA, which a 1N40001 should pass with ease. But the 1 second flash rate is odd. Perhaps the supply is doing funny things. There should be a current limiting resistor, either one for each LED (about 500 ohms) or one in the supply (about 40 ohms).

by mikerogerswsm
April 23, 2018
Add comment...

Please sign in or create an account to comment.


Your Answer

You must log in or create an account (free!) to answer a question.

Log in Create an account


Go Ad-Free. Activate your CircuitLab membership. No more ads. Save unlimited circuits. Run unlimited simulations.

Search Questions & Answers


Ask a Question

Anyone can ask a question.

Did you already search (see above) to see if a similar question has already been answered? If you can't find the answer, you may ask a question.


About This Site

CircuitLab's Q&A site is a FREE questions and answers forum for electronics and electrical engineering students, hobbyists, and professionals.

We encourage you to use our built-in schematic & simulation software to add more detail to your questions and answers.

Acceptable Questions:

  • Concept or theory questions
  • Practical engineering questions
  • “Homework” questions
  • Software/hardware intersection
  • Best practices
  • Design choices & component selection
  • Troubleshooting

Unacceptable Questions:

  • Non-English language content
  • Non-question discussion
  • Non-electronics questions
  • Vendor-specific topics
  • Pure software questions
  • CircuitLab software support

Please respect that there are both seasoned experts and total newbies here: please be nice, be constructive, and be specific!

About CircuitLab

CircuitLab is an in-browser schematic capture and circuit simulation software tool to help you rapidly design and analyze analog and digital electronics systems.