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Building a closing switch using household items.

sanchj22

Nov 27, 2019
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A project of mine requires I build a closing switch (voltage fuse) that functions for both DC and AC currents, using only items we can find around the house (no off the shelf components). Household items include copper wire, coins, pencil lead, etc.

At a high enough voltage, the switch must close the circuit to draw away the high currents from other circuit components. This switch should also be reusable.

At least for the AC part, my first thought was using an inductor to create a magnetic field that could close a magnetized switch (piece of metal), which would close the open circuit and short the circuit to ground. However, I don't know how I could get this to work for DC currents, which wouldn't cause a magnetic field. It seems that the open switch would just reach a high potential but have no force causing it to shut. Any guidance on the physics and theory on getting a switch to shut in both AC and DC conditions like this?
 

Minder

Apr 24, 2015
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A

At least for the AC part, my first thought was using an inductor to create a magnetic field that could close a magnetized switch (piece of metal), which would close the open circuit and short the circuit to ground. However, I don't know how I could get this to work for DC currents, which wouldn't cause a magnetic field.

Don't let Michael Faraday hear you say that!:rolleyes:
M.
 

davenn

Moderator
Sep 5, 2009
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I don't know how I could get this to work for DC currents, which wouldn't cause a magnetic field.

Don't let Michael Faraday hear you say that!:rolleyes:
M.

agreed


@sanchj22 you have some strange understandings and possibly some very dangerous switch ideas

what sort of voltages/currents are you wanting to switch ? this could be very dangerous
and why switching to ground ? again this could be very dangerous

which would close the open circuit and short the circuit to ground.

yeah … very dangerous

I am going to close this thread
PM me with what you are really trying to achieve and voltages and currents you are wanting to work with and I can decide if it is safe enough to reopen the thread


Dave
 

sanchj22

Nov 27, 2019
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Nov 27, 2019
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This is the problem statement. Having a magnetic switch was my first thought, or also a metallic strip that would bend at high enough heats which would cause the switch to close.
 

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Alec_t

Jul 7, 2015
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An interesting challenge, particularly with the timing/frequency limitations!
I wonder what 12V battery can put out enough current to meet the '1MA' requirement, and what you can use that isn't available (somewhere) 'off-the-shelf' these days?
 
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