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# Electrical transformer watch

1. A transformer has a turn ratio of 10:1. If the primary voltage is 180v and the primary current 4A what is the secondary voltage and current?
2. (Original post by michaelfaley)
A transformer has a turn ratio of 10:1. If the primary voltage is 180v and the primary current 4A what is the secondary voltage and current?
Np/Ns=10 (because turns ratio = 10:1)

Np/Ns=Vp/Vs is in the formula sheet

divide both sides by Vp

Np/(NsVp)=1/Vs

NsVp/Np=Vs

power out = power in
IsVs=IpVp

divide both sides by Vs
Is=(IpVp)/Vs

could go further and show
Is/Ip=Vp/Vs
and because
Np/Ns=Vp/Vs
Is/Ip=Np/Ns

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