Driving large LED array

I have a radar unit that has an single red/green led output and want to amplify this to operate a larger display. The system is 12Vdc and the new led array load is 91mA. What is the best way to do this? Thanks.

by Nzdude
April 06, 2017

1 Answer

Answer by mikerogerswsm

I assume that the radar unit output is 0V for green and +12V for red. If the larger display is the same polarity then all you need to do is use a double emitter follower: PNP transistor with collector to 0V, base to input, emitter to output and NPN transistor with collector to +12V, base to input and emitter to output. Almost any transistor will do, it is low voltage, low current and low power. If the larger display has four wires then take one pair from NPN emitter (+) to 0V (-), and the other pair from PNP emitter (-) to +12V (+). It would be good practice to add a 1A fuse in the +12V supply. Enjoy!

+2 votes
by mikerogerswsm
April 08, 2017

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.