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I'm currently learning about electronics so I bought myself a variable power supply - something I think will be useful over the coming years. I would like to know if I use a hot wire cutter (most likely nichrome wire? polystyrene cutting pen from ebay - link at the bottom of this post) then could I use my variable power supply to power it rather then getting a separate transformer?

The power supply I have is around 20v up to 25a and it has a dial to change the voltage. I was wondering if I dialled the voltage to 6v will the heating element just take enough current required to heat up or will it be greedy, shoot up to 20 or so amps then melt? If so then might there be a good option to limit the current?

Just to assure - I looked through many posts on here and couldn't find something specific to this (perhaps I just wasn't sure what to look for and peoples posts on using a variable pot to control power to a heating element says all).

https://www.ebay.co.uk/itm/273337454116

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The Styrofoam Cutter needs a supply of 6 V, 2.5A

What you need to do is:

  • Make sure you supply 6 V to the Styrofoam Cutter as 6 V is what it needs
  • Make sure that the supply is capable of delivering at least 2.5 A as that's what the Cutter will draw.

As long as you supply the right voltage then the load (the Cutter) will draw the current that it needs. The supply then needs to be able to deliver that current.

You mention that your supply can deliver up to 25 A so that is more than sufficient to supply 2.5 A to the Cutter.

If there is a current limit option on the supply then you can optionally set that to a little above what the Cutter needs so in your case I would set it to 3 A to 4 A. Than if the Cutter develops a fault and short-circuits at least the current is limited. With your 25 A supply that is important as 25 A is a lot of current.

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  • \$\begingroup\$ Thank you, that's very informative :) Also excellent idea on that - it does have a 3 A option at the front so I'll be sure to use it. \$\endgroup\$ – PeteB Sep 23 '18 at 18:21

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