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914 Posts

fifychewy said:total resistance^-1 = r^-1 + r^-1 + r^-1

Thanks for that.fify

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914 Posts

Glad to help.chewy said:Thanks for that.

your specific problem

Rt = 1/50 + 1/100 + 1/100

Rt = 0.02 + 0.01 + 0.01

Rt = 0.04

Yep Im using that mate.You know about the reciprocal button on the calculator right (x-1)? Makes these calcs so much quicker

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2,173 Posts

You would not believe how many Calculators don't have that button...You know about the reciprocal button on the calculator right (x-1)? Makes these calcs so much quicker. (don't mean to be insulting but a lot of people in my class didn't know this and were using division all the time)

Parallel Circuits:

Circuit resistance --- is: (1 / (1/R1 + 1/R2 + 1/R3 + ...)

Voltage --- The voltage drop across all components connected in parallel must equal the supply voltage.

Current --- Total circuit current is equal to the sum of all parallel branch currents

Power --- Total circuit power is equal to the sum of the branch current times the supply voltage. In other words, the I x E power dissipated in each branch of a paralle circuit must add up to be equal to total circuit current time supply voltage.

GO VA

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3,309 Posts

Nope, wrong answer

your specific problem

Rt = 1/50 + 1/100 + 1/100

Rt = 0.02 + 0.01 + 0.01

Rt = 0.04

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1,948 Posts

Product over the sum only works with 2 resistances at a timeit's in parallal, R1 x R2 x R3/ R1 + R2 + R3...

Not leaving my VA Boys (ACC) to go look at School Books!

He has to un-X^-1 his answer no?Nope, wrong answer

Not according to my "ciphering"!Nope, wrong answer

Too late for this tonight, but I forgot the 1/RT

so.......

1/.04 = 25 ohm

My answer key says 2.5 ohms.Not according to my "ciphering"!

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1,948 Posts

Should be 25 ohmsMy answer key says 2.5 ohms.

Just means putting what follows it up as an exponent.I know that... now

I'm trying to figure out what ^ meanx......

Seriously? Thats the 3rd typo in this ****ing work book.Should be 25 ohms

If two R are the same, you can take half of the total of the two.

So (2) 100 R would be 50

Now since the other R is 50 you now have (2) 50 R

So half of 50 = 25

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