Voltage generated from magnet being dropped through copper tube v.s. coil

Thread Starter

Ray Bryant

Joined Jan 31, 2019
16
To give some background:

If I had a copper coil with the ends attached to allow current to flow, and I dropped a magnet through it I would generate an emf I could measure with a voltmeter. If I repeated the same experiment with a copper tube would I be able to somehow do the same thing?

Going a bit further, if I attached an LED in series to my coil set up and dropped a strong enough magnet through it, I would see it light up.
Is the same possible with a copper tube?
 

wayneh

Joined Sep 9, 2010
17,149
To give some background:

If I had a copper coil with the ends attached to allow current to flow, and I dropped a magnet through it I would generate an emf I could measure with a voltmeter. If I repeated the same experiment with a copper tube would I be able to somehow do the same thing?

Going a bit further, if I attached an LED in series to my coil set up and dropped a strong enough magnet through it, I would see it light up.
Is the same possible with a copper tube?
No. Current would flow, but from point to point within the metal of the tube. There would be nowhere to capture some of the emf since the copper of the tube would ensure that even a tiny emf gets “shorted”.
 

Bernard

Joined Aug 7, 2008
5,781
The coil can produce enough current to flash a LED.

. My coil is about 25 mm dia. X 20 mm long, & 3 mm deep wound with .11 mm wire.
 
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