When to use this calculator
Find ideal transformer secondary current from current and turns ratio. Assumes ideal power transfer and compatible AC operating conditions; losses and magnetising current are ignored.
Explore the ac power & reactance calculators for other questions in this topic. For a related calculation, use the Battery C Rate Calculator: Express charge or discharge current relative to battery capacity.
PUTTING IT INTO PRACTICE
Transformer Secondary Current: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Primary current (A) | 1 |
| Primary turns (integer) | 1,000 |
| Secondary turns (integer) | 100 |
| Result | 10 A |
- Check the input labels and enter the example values above.
- Apply the relationship: Ideal secondary current = primary current × primary turns/secondary turns.
- The result is 10 A, rounded for display.
How to interpret your result
Assumes ideal power transfer and compatible AC operating conditions; losses and magnetising current are ignored.
Use RMS values in the AC power relationships. Apparent power is measured in VA and real power in watts. Pure-sine conversions and balanced three-phase equations only apply under their stated assumptions.
Frequently asked questions
Why can volt-amps differ from watts?
Apparent power is the RMS voltage-current product, while real power also reflects power factor. They are numerically equal only at a power factor of one.
When is the transformer secondary current calculator useful?
Find ideal transformer secondary current from current and turns ratio. Assumes ideal power transfer and compatible AC operating conditions; losses and magnetising current are ignored.
How do I use the transformer secondary current calculator?
Enter primary current (a), primary turns (integer), secondary turns (integer). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Ideal secondary current = primary current × primary turns/secondary turns.
What should I check before using the result?
Assumes ideal power transfer and compatible AC operating conditions; losses and magnetising current are ignored.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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