Transformer Turns Ratio Calculator
Calculate transformer turns ratio, secondary voltage, and secondary current from primary specifications.
V
V
A
Turns Ratio (Np/Ns)
10.00 :1
Secondary Current5.00 A
Apparent Power60.0 VA
Turns Ratio (Np/Ns) vs Primary Voltage
Transformer Turns Ratio
Formulas
Np/Ns = Vp / Vs
Is = Ip x Np/Ns (ideal transformer)
Power = Vp x Ip = Vs x Is
An ideal transformer conserves power. Real transformers have 90-98% efficiency due to copper and core losses.
Example Calculation
120 V primary to 12 V secondary, 0.5 A primary current.
- 01Turns ratio = 120 / 12 = 10:1
- 02Secondary current = 0.5 x 10 = 5 A
- 03Power = 120 x 0.5 = 60 VA
Frequently Asked Questions
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