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I would like a little insight on choosing a Mosfet for a hotwire cutter. The wire runs 12v @ 2A

I am planning on using a 555 PWM circuit to control the temp on the wire. I plan to use the PWM signal through a mosfet to do this.

I have never used a mosfet for this before. If there is one that would run fine with out a heat sink that would be awesome as the whole project has to be as low cost as possible.

If anyone could recommend one or two I will have a look at the specs. I can post a circuit diagram if needed, not quite complete yet.

Olin Lathrop
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Ashley Hughes
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1 Answers1

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In this answer I explain the most relevant parameters when choosing a FET, and use the FDC855N as an example. Like asker of that question you have literally thousands of FETs that fit the bill, like the FDC855N, for example:

\$I_D\$ max: 6.1 A
\$V_{DS}\$ max: 30 V
\$R_{DS(ON)}\$ max: 27 mΩ at 10 V

The low \$R_{DS(ON)}\$ means that power dissipation will only be 100 mW.

For heating you don't need a high PWM frequency, so switching losses can also be kept low.

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stevenvh
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