# I have a device that needs #12"V"# and #2"A"# to run. I have a #28"V"# source. How do I make the device work with one or more #3Omega# resistors?

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This was a question on a test and I assume it implies there needs to be exactly #12"V"# dropped across the device and #2"A"# through it. I put the device in series with an #8Omega# equivalent resistor (a series of two #3Omega# resistors and two pairs of three #3Omega# resistors in parallel).

This was a question on a test and I assume it implies there needs to be exactly

##### 1 Answer

May 19, 2017

The device is rated to run at

The excess voltage must drop, while it draws

Using Ohm's law

we get

To make a

- Two numbers of
#3Omega# resistors connected in series#=6Omega# resistance. - Three numbers of
#3Omega# resistors connected in parallel#=1Omega# resistance

Hence,#8Omega# resistance#=# Series connection of Two#3Omega# resistors and two sets of three#3Omega# resistors connected in parallel.