Need some help drawing a circuit!

Thread Starter


Joined May 28, 2012
Hi im a student and i would say drawing circuits would not be my best field in engineering. I have made a project but dont have a drawn circuit with my finished circuit.

My circuit is powered by a 12V power supply, it contains 85 LED's which are connected in 3's with a resistor of 1K ohms across each of these 3. There is a PIR sensor connected with a 12V relay to allow the PIR to detect movement.

I need some help on drawing this circuit on multisim to complete my project for college.


Joined Apr 30, 2011
The first thing you need to do is figure out how to divide 85 evenly by 3. Use your best engineering math. ;)

Put the power source on the left, the control circuitry in the middle and the outputs on the right. Since you have a repeating group of 3 LEDs and a resistor, you can show them as such instead of drawing all 84 LEDs and 28 resistors.

You can't go wrong following the advice of Horowitz and Hill.
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