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I have a wolphram wire that works as a heating element. It's resistance is 1 Ohm. The wire hits the target temperature when it passes 1A of current. I can achieve this current by applying 1V across the wire. Since the device is powered by USB which outputs 5V I need to step the voltage down to 1V somehow.

I believe one solution would be to use a step-down power supply like this one banggood.

Are there any other solutions?

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  • \$\begingroup\$ That one that you put the link of has MP2307 as regulator chip. According to datasheet its output can be as low as 0.93VDC. Seems that it can be used. I suggest you to put a a series resistor (i.e. between the port's +5V and the + input of the circuit) like 1 Ohm or so to slow the startup down and to protect the port. \$\endgroup\$
    – Rohat Kılıç
    Commented Jan 15, 2020 at 5:41

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If you don't mind being inefficient and violating USB standards, most computer USB ports will put out 1 A without complaint, so you could just use a series resistor.

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    \$\begingroup\$ Then he'll get four times as much heat from the resistor as from the heating wire - not terribly efficient. :) \$\endgroup\$
    – Peter Bennett
    Commented Jan 15, 2020 at 5:11
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    \$\begingroup\$ That resistor will dissipate 4 Watts at first. Even if the dissipation gets lower as the tungsten wire warms up the dissipation will be high enough. Maybe you should have explained how to cool that series resistor. \$\endgroup\$
    – Rohat Kılıç
    Commented Jan 15, 2020 at 5:35

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