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Q & A: magnets and LED in parallel

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Most recent answer: 09/17/2018
Q:
I made an electromagnet for my kid's project. Two batteries, bolt and copper wire. Al works fine. I then wanted to add an LED light in parallel too indicate the magnet has got current. The LED works fine by itself but when we connect the magnet wires - No light and no magnetism. Can this be done? What do I do wrong. Regards
- Franscois (age 47)
South Africa
A:

It's not surprising that the magnet has low enough resistance to draw so much current from the batteries that the voltage dropped below the minimum needed for the LED. I'm a little surprised that the LED draws enough current in the parallel circuit to keep the magnet from working, because the LED isn't even visibly lit. Perhaps the batteries just rand down from supplying all that current. Your parallel circuit should work, but you may need fresh batteries, and probably larger ones with more ability to supply current. It sounds like the rated voltage of your present ones is about right.

Mike W.


(published on 09/17/2018)

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