# Dissipation of watts

Thread Starter

#### tjjam2003

Joined Apr 5, 2006
22
What voltage is required to cause a dissipation of 10 watts in a resistor when the current through the resistor is 150mA?? The book says 66.67 volts.
Can you please help the newbie out???

#### rodn.m

Joined May 3, 2006
12
Originally posted by tjjam2003@Apr 9 2006, 12:16 AM
What voltage is required to cause a dissipation of 10 watts in a resistor when the current through the resistor is 150mA?? The book says 66.67 volts.
Can you please help the newbie out???
[post=15976]Quoted post[/post]​
P=E*I
where E=66.67 volts
I=150 mA
150/1000=.15*66.67=10watts

#### radiosmoke

Joined May 30, 2006
17
Originally posted by tjjam2003@Apr 8 2006, 07:16 AM
What voltage is required to cause a dissipation of 10 watts in a resistor when the current through the resistor is 150mA?? The book says 66.67 volts.
Can you please help the newbie out???
[post=15976]Quoted post[/post]​
-------------
The book is asking for you to find out what the voltage is.
That's why they didn't give you the voltage to start with.

you need to use the formula below to find out what the voltage should be, when only the power and current are known. If you use voltage to prove your answer, you are going at it backwards from what the book is getting at and that isn't the way to use the formula.
so use
V = W ÷ A

10w/150mA = 66.6volts

Hope this helps

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