SOLUTION: A transformer has a secondary voltage of 140 volts and a secondary current of 3.5 amps. If the primary current is 10 amps, what is the primary voltage? (In this case, the voltages

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Question 1182453: A transformer has a secondary voltage of 140 volts and a secondary current of 3.5 amps. If the primary current is 10 amps, what is the primary voltage? (In this case, the voltages and currents are inversely proportional.)
Found 2 solutions by ikleyn, mananth:
Answer by ikleyn(52799) About Me  (Show Source):
You can put this solution on YOUR website!
.
A transformer has a secondary voltage of 140 volts and a secondary current of 3.5 amps.
If the primary current is 10 amps, what is the primary voltage?
(In this case, the voltages and currents are inversely proportional.)
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The basic formula from electricity is


    I%5B1%5D%2AU%5B1%5D = I%5B2%5D%2AU%5B2%5D


using standard notations.


From the basic formula,


    U%5B1%5D = %28I%5B2%5D%2AU%5B2%5D%29%2FI%5B1%5D.


Now substitute the given data and calculate.

Happy calculations (!)



Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
The general formula for voltage current and number of turns in a transformer is

+Np%2FNs+=+Vp%2FVs+=+Is%2FIp
where N is number of turns is the voltage
I is the current
p is primary coil
s secondary coil
Vp%2F140+=+3.5%2F10
Vp = 14 *3.5 =49 Volts