Finding Voltage, Simple Circuit

M

mikali

Member

• Mar 6, 2014

• #1

Need to find the voltage of (Vab). When I apply the KVL for the two loops that incorporate (Vab) I get stuck, any help would be great. Thanks

 

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JimB

Super Moderator

Most Helpful Member

• Mar 6, 2014

• #2

I am not too sure about Mrs Kirchoffs little boy, but consider the following:

What is the voltage across the two series connected resistors?
What is the voltage across one of the resistors?

You now should have enough information to calculate the voltage between points a and b.

JimB

 

M

mikali

Member

• Mar 6, 2014

• #3

Ahh, I think I got it. I redrew it and it looks like the two Voltage sources are in series, so we can add them up, and it also looks like there in a Voltage Divider set-up. I got 9v for (Vab).Am I correct....I hope

 

JimB

Super Moderator

Most Helpful Member

• Mar 6, 2014

• #4

Correct!

The two voltage sources are in series, but with opposite polarity, so the voltage across the resistors is 12 - 6 = 6 volts.
The two resistors are of equal resistance, so the voltage across each resistor is 6v/2 = 3volts.

From points a to b, the voltage is 6+3 = 9v or 12-3 = 9v.

JimB

 

M

mikali

Member

• Mar 6, 2014

• #5

yay, thanks. JimB...More like Jim B good at teaching