Ideal Transformer Calculator
Free calculate voltage, current, turns ratio, and power for ideal transformers. solve for any variable.
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What is an Ideal Transformer?
An ideal transformer is a theoretical device that transfers electrical energy between two circuits through electromagnetic induction with 100% efficiency and no losses.
In an ideal transformer, the voltage ratio equals the turns ratio, the current ratio is the inverse of the turns ratio, and power is conserved (input power = output power). Real transformers have losses due to resistance, core losses, and leakage flux.
Transformers are essential in power distribution, stepping up voltage for long-distance transmission and stepping down for safe use in homes and businesses.
Ideal Transformer Formulas
Voltage Ratio
Voltage is proportional to turns
Current Ratio
Current is inversely proportional to turns
Power Conservation
V_p × I_p = V_s × I_s
Turns Ratio
Transformation ratio
How to Calculate
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1
Identify what to solve for
Determine whether you need voltage, current, or turns ratio.
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2
Use the appropriate formula
For voltage: V_p/V_s = N_p/N_s. For current: I_p/I_s = N_s/N_p.
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3
Verify power conservation
Check that V_p × I_p = V_s × I_s (for ideal transformer).
Practical Examples
Example 1: Step-Down Transformer
A transformer has 1000 primary turns and 100 secondary turns. If primary voltage is 120 V, what is secondary voltage?
Solution:
V_s = V_p × (N_s/N_p) = 120 V × (100/1000)
V_s = 12 V
Example 2: Current Calculation
If primary current is 1 A and turns ratio is 10:1, what is secondary current?
Solution:
I_s = I_p × (N_p/N_s) = 1 A × (10/1)
I_s = 10 A
Applications
Power Distribution
Step-up transformers increase voltage for efficient long-distance transmission, step-down transformers reduce voltage for safe use.
Electronics
Power adapters, chargers, and voltage converters use transformers to match device requirements.
Industrial
Motor control, welding equipment, and industrial machinery use transformers for voltage and current matching.
Audio Equipment
Audio transformers provide impedance matching and signal isolation in amplifiers and recording equipment.
Frequently Asked Questions
What is a step-up transformer?
A step-up transformer has more secondary turns than primary turns (N_s > N_p), increasing voltage and decreasing current. Used for power transmission.
What is a step-down transformer?
A step-down transformer has fewer secondary turns than primary turns (N_s < N_p), decreasing voltage and increasing current. Used in power adapters and wall outlets.
Why is power conserved in ideal transformers?
Ideal transformers have no losses. All input power is transferred to the output. Since P = V×I, if voltage increases, current must decrease proportionally.
What are real transformer losses?
Real transformers have copper losses (resistance), core losses (hysteresis and eddy currents), and leakage flux. Efficiency is typically 95-99%.
Can transformers work with DC?
No, transformers only work with AC. DC current doesn't create a changing magnetic field, so no voltage is induced in the secondary coil.