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## Parallel resistance

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### Parallel resistance

I recently started reading a book on basic electronics theory and came across a confusing concept. Apparently total equivalent resistance of a circuit containing parallel resistors is always less than the value of the smallest resistor. I don't understand how that is possible. How could it be that in a circuit containing two resistors, R1=1000 and R2=3000, total equivalent resistance is equal to 750 ohms. If my entire current traveled through R1 I could achieve greater resistance. Why is it that adding a resistor of even greater value would diminish my total resistance? If anyone could help me out it would be greatly appreciated.
Cube_Code

Posts: 1
Joined: Wed Jun 27, 2012 5:00 pm

### Re: Parallel resistance

According to Ohms Law the current through a resistor is proportional to the voltage acropss it, ie. Current (I) = V / R.

So if you have a supply voltage of 10V, the current through the 1000ohms resistor= .01A. And the current through the 3000ohm resistor would be .00333A. That makes the current through both resistors in parallel = .01A + .00333A = .01333A.

Again, from Ohms Law, if 10V produces a current of .01333A through the total resistance, the resistance must be 10/.0133A = 750ohms.

I hope that explains it.
pebe

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Joined: Tue Dec 09, 2003 11:12 pm
Location: Ellon, Scotland