Transformer Equations
2 guided lessons · 18 checks · 6. Magnetism and Electromagnetism → Electromagnetic Induction
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The turns-ratio equation in use
One relationship runs every transformer calculation: primary voltage over secondary voltage equals primary turns over secondary turns. Read the turns, read the known voltage, and the unknown comes out — up for a step-up with more secondary turns, down for a step-down with fewer.
What you know already
Two equations run every transformer problem: the turns ratio links voltages to turns, and the ideal power balance VpIp = VsIs links voltage to current. This note drills both — step-up arithmetic with sanity checks, and the grid's trade of voltage for current.
Key points of understanding
- The relationship is: primary voltage / secondary voltage = primary turns / secondary turns.
- The input voltage is across the primary; the output is across the secondary.
- Rearranged, secondary voltage = primary voltage × secondary turns / primary turns.
- More secondary turns than primary means the voltage is stepped up.
- Substitute in the ratio form and keep units consistent — volts in, volts out.
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1.The turns-ratio equation in use
One relationship runs every transformer calculation: primary voltage over secondary voltage equals primary turns over secondary turns. Read the turns, read the known voltage, and the unknown comes out — up for a step-up with more secondary turns, down for a step-down with fewer.
Key points
- The relationship is: primary voltage / secondary voltage = primary turns / secondary turns.
- The input voltage is across the primary; the output is across the secondary.
- Rearranged, secondary voltage = primary voltage × secondary turns / primary turns.
- More secondary turns than primary means the voltage is stepped up.
- Substitute in the ratio form and keep units consistent — volts in, volts out.
Guided content from the SME authoring corpus — note rn_hYbhpMKCjdqM8zQF, pinned at 6312d659ec0d · promoted SyllabAI/syllabai-resources b3caaaa90c5e