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?
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.