# Using Current and Voltage Dividers

## Homework Statement:

Find:
A) vo
B) io
C) power dissipated in 6 ohm resistor
D) power developed by current source

## Relevant Equations:

Current and Voltage divider equations. Ohm's law. A) Find the equivalent resistance (10 ohms). Find the voltage of the current source (4.2*10 = 42 V). Use a voltage divider to find vo = 42*(20/(10+20))=28V. My question is why do we need to add 10, which is R equivalent to 20 again? I thought I could just put 10 in the denominator, since this is R equivalent.
B) Similar questions. Voltage across 90 ohm resistor = 42*((90 in parallel with 10)/(6+(90 in parallel with 10)) = 25.2 V. Current across 90 ohm resistor = 25.2/90 = 0.28 A.
C) Power dissipated by 6 ohm resistor = (Voltage across current source - voltage across 90 ohm resistor)^2 / 6. My question here is how do I know which is positive and which is negative here in terms of subtraction/addition.

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kuruman
Homework Helper
Gold Member
Please post the full statement of the problem before seeking help. We cannot help you without it. For example, where does the 42 come from?

Please post the full statement of the problem before seeking help. We cannot help you without it. For example, where does the 42 come from?
sorry, the only thing I left out was that ig, the current source, is 4.2 A

kuruman