voltage in parrallel circuits

Joined Mar 4, 2006
1
How do you find the voltage in a parrallel circuit if it is not given?

Ex. if you had 3 resistor 1ohm,2ohm, and 3ohms split into 3 branches with a 500mA current

hgmjr

Joined Jan 28, 2005
9,029
Originally posted by VADER332@Mar 4 2006, 05:02 PM
How do you find the voltage in a parrallel circuit if it is not given?

Ex. if you had 3 resistor 1ohm,2ohm, and 3ohms split into 3 branches with a 500mA current
[post=14667]Quoted post[/post]​
Without a diagram to go by it is tough to figure out what you have described.

hgmjr

beenthere

Joined Apr 20, 2004
15,808
Hi,

You have not given enough data to us. With the 3 resistors in parallel, the equivalent resistance will be less than the smallest discreet resistor, so Rt will be under 1 ohm. With no additional resistance given, we can only suggest a very low source voltage that will source the 500 mills current.

Grant

Joined Mar 5, 2006
17
Originally posted by VADER332@Mar 5 2006, 09:02 AM
How do you find the voltage in a parrallel circuit if it is not given?

Ex. if you had 3 resistor 1ohm,2ohm, and 3ohms split into 3 branches with a 500mA current
[post=14667]Quoted post[/post]​
The three resistances in parallel will give a total resistance of 0.55 Ohms-(using resistances in parallel equation). If you have a total current of 500mA then simply using Ohm's Law we have E=IxR
(500mA is 0.5 Amps)
E= 0.5x0.55
E= 0.275 Volts
Hope this explains it to you.
Cheers,
Grant

alva

Joined Dec 14, 2005
12
Originally posted by VADER332@Mar 4 2006, 05:02 PM
How do you find the voltage in a parrallel circuit if it is not given?

Ex. if you had 3 resistor 1ohm,2ohm, and 3ohms split into 3 branches with a 500mA current
[post=14667]Quoted post[/post]​

If the current is 500 mA before splitting up between the 3 branches, then you need to solve R then you can get the voltage. E =IR.

For parallel resistors you can simply add the ohm value reciprocals and then use the reciprocal of the total. e.g. 1/1 + 1/2 + 1/3 = 6/6 + 3/6 + 2/6 = 11/6 = 6/11 =.545 or .55 ohms; then solve for E : E= .55 ohm x .5 A = .275V
And in a parallel circuit the total resistance will always be less than the lowest ohm resistor, in this case 1 ohm.