Single Phase Transformer Calculator

Single-Phase Transformer Voltage & Current Estimator

Input Fields

Primary Voltage

Vₚ

V

Voltage applied to the primary coil

Primary Turns

Nₚ

Number of turns in primary coil

Secondary Turns

Nₛ

Number of turns in secondary coil

Primary Current

Iₚ

A

Current flowing into the primary winding

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Calculate automaticallyIf enabled, the result will update automatically when you change any value.

Your Results

Secondary Voltage (Vs)

Secondary Current (Is)

Turns Ratio (Np:Ns)

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Transformer Voltage and Current Formulas

$$\frac{V_p}{V_s} = \frac{N_p}{N_s}$$ $$\frac{I_p}{I_s} = \frac{N_s}{N_p}$$ $$P = V \cdot I$$

Where:

• $$V_p$$ = primary voltage (V)
• $$V_s$$ = secondary voltage (V)
• $$N_p$$ = number of primary turns
• $$N_s$$ = number of secondary turns
• $$I_p$$ = primary current (A)
• $$I_s$$ = secondary current (A)
• $$P$$ = apparent power (VA)

These formulas assume an ideal transformer (no losses).

Single Phase Transformer – Calculation Example

Given:

• $$V_p$$ = 240 V
• $$V_s$$ = 24 V
• $$I_s$$ = 5 A

Calculation:

1. $$\frac{V_p}{V_s} = \frac{240}{24} = 10 \Rightarrow \text{Turns ratio} = 10:1$$
2. $$I_p = \frac{I_s}{\text{Turns ratio}} = \frac{5}{10} = 0.5~\text{A}$$
3. $$P = V_s \cdot I_s = 24 \cdot 5 = 120~\text{VA}$$

Single-phase transformers are widely used in residential and light commercial electrical systems. This calculator allows you to compute voltage, current, power, or turns ratio depending on known parameters. It’s especially helpful for transformer selection, voltage conversion, and understanding power flow in AC circuits. While these formulas assume ideal conditions, they provide a close approximation for design and learning purposes.