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What is minimum size resistor in watts to use with a 9 volt 900 ohm resistor?
Wiki User
∙ 15y ago
Take your pick:
P = V x I (Power = Voltage x Current)
or:
P = V2 / R (Power = Voltage2 / Resistance)
or:
P = I2 *R (Power = Current2 x Resistance)
(the last two equations come from combining the ohms law equation R=V/I with the power equation P=VxI)
In the question above you have resistance and voltage therefore:
P = V2 / R = 92 / 900 = 0.090W = 90mW
(i believe 0.125W is the smallest resistor you can get)
hope that helps
Wiki User
∙ 15y ago
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