# what can be used as the dummy load on a converted power supply

I dont have a 10 watt 10 ohm resistor for the dummy load but I do have several others like 7 watt 6 kohm ,or 5 watt 300 ohm and some 10 watt 7 kohm can I use any of these if so how to wire them

active| newest | oldestIt's not the watt rating, it's the 'make sure you draw 2-10 watts' part that is important. The watt rating is just how much heat it can dissipate without exploding!

Using ohms law you can calculate how much power it will dissipate:

V= IR

Volts = Amperes (Current) * Ohms (Resistance)

at 5 volts:

300 ohms

5 = I*300

I = 5/300 = 0.0166 Amperes

V*I = Watts

5 * 0.0166 = .083 watts. <<< NOT ENOUGH!

Say you want to draw 3 watts, work it backwards.

at 5 volts, 3 watts is 3W/5V = 0.6 Amps

V = IR

5 = 0.6 R

R = 5/0.6

R = 8.3 Ohms.

You need an approximately 8 ohm resistor RATED FOR better than 3 watts, 5-10 watts is a safe rating to make sure it doesn't blow up.