- #1
jegues
- 1,097
- 3
Homework Statement
You are given a device with which to operate with an input resistance of 50 W. The device requires 9 V to operate. However, the only available power supply is a 12 V source.
Part A:Using only resistors, design an interface circuit to lower the 12 V to 9 V for operating the device.
Part B:If the power supply has a 10 W internal resistance, what will be the voltage of the load?
Part C:How would you adjust it so that you get a 9 V voltage again?
Homework Equations
[tex]V_{out} = \frac{R_{2}}{R_{1} + R_{2}} \cdot V_{in}[/tex]
The Attempt at a Solution
For Part A, can't I simply use a voltage divider to drop the 12V to 9V? If I set ,
[tex]R_{1} = 1 \Omega[/tex]
and,
[tex]R_{2} = 3 \Omega[/tex]
Then I should obtain a [tex]V_{out} = 9V[/tex].
Part B & C is where I start to get a little confused.
For Part B, if the power supply has 10 W internal resistance and it says in the question that the device has an input resistance of 50 W does that mean the other 40 W will be on the load?
Part C is hooked into Part B so until I fully understand that, I don't think I have a shot at answering Part C.
Any ideas/comments/suggestions?
Thanks again!