Electronic – Feeding a load with very low impedance

powershort-circuitvoltage divider

I need to provide a reasonable amount of power (40-50W) for a heat pillow, how should I design the power supply circuit if the load (Enamel Insulated Resistance Heating Wire) is 2,5 ohm.

I can't wrap my head around how to feed such a load without getting short circuits on one hand and voltage divider taking all the power on the other hand.

Thanks in advance!

Best Answer

You should not be using a voltage divider. What you need is a mains transformer.

50W in 2.5 ohm that's 11.1 V, 4.5A.

So I would get a mains transformer with an output of 12 V AC, of at least 5 A so 60 W or 60 VA. Also use THICK wires from the transformer to your load. Look at the wires in the transformer, about that thick when they're solid so for stranded cable you need something even thicker.

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