Transformer Turns-per-Volt
TPV = 1 / (4.44 · f · Bmax · A)
Quick answer
This calculator solves Turns/Volt = 1 / (4.44 × f × Bmax × A) for Turns per Volt. With Frequency 1 kHz, Peak Flux Density 0.5 T, Core Area 10 cm², the result is 0.4505. It solves in 4 directions, so you can enter the values you have and get the one you need.
Calculator
Formula
Description
Turns-per-volt is the practical design figure that tells a transformer winder how many turns to put on each winding per volt of desired output. It is the reciprocal of the EMF equation per volt and depends only on the frequency, the chosen working flux density, and the core area. Multiply turns-per-volt by the winding voltage to get the number of turns.
Variables
- TPV — Turns per volt (turns/V)
- f — Frequency (Hz)
- Bmax — Working flux density (T)
- A — Core area (m²)
Practical Notes
A common shop rule for 50 Hz iron-core transformers is TPV ≈ 1/(4.44·f·B·A); designers add a few percent extra turns to the secondary to offset winding resistance and improve regulation.
Symbols and units
| Symbol | Meaning | Default unit | Accepted units |
|---|---|---|---|
| TPV | Turns per Volt | — | — |
| f | Frequency | Hz | Hz, kHz, MHz, GHz |
| Bmax | Peak Flux Density | T | G, mT, T |
| A | Core Area | cm² | mm², cm², m² |
Step by step
- 1. What you know: Frequency 1 kHz, Peak Flux Density 0.5 T, Core Area 10 cm²
- 2. The relation: Turns/Volt = 1 / (4.44 × f × Bmax × A)
- 3. Substitute: f = 1 kHz, Bmax = 0.5 T, A = 10 cm²
- 4. Result: Turns per Volt = 0.4505
Worked examples
Minimum range
Given: Frequency 5 Hz, Peak Flux Density 10 G, Core Area 10 mm²
Result: Turns per Volt = 4.5 × 10⁶
Low range
Given: Frequency 50 Hz, Peak Flux Density 10 mT, Core Area 1 cm²
Result: Turns per Volt = 4505
Typical
Given: Frequency 1 kHz, Peak Flux Density 0.5 T, Core Area 10 cm²
Result: Turns per Volt = 0.4505
High range
Given: Frequency 20 kHz, Peak Flux Density 1.5 T, Core Area 100 cm²
Result: Turns per Volt = 7.51 × 10⁻⁴
Maximum range
Given: Frequency 0.2 MHz, Peak Flux Density 15 T, Core Area 0.1 m²
Result: Turns per Volt = 7.51 × 10⁻⁷
Solving for each variable
Solve for Turns per Volt
Frequency 5 Hz, Peak Flux Density 10 G, Core Area 10 mm² → 4.5 × 10⁶
Solve for Frequency
Turns per Volt 0.025, Peak Flux Density 10 G, Core Area 10 mm² → 0.9009 GHz
Solve for Peak Flux Density
Turns per Volt 0.025, Frequency 5 Hz, Core Area 10 mm² → 180200 T
Solve for Core Area
Turns per Volt 0.025, Frequency 5 Hz, Peak Flux Density 10 G → 1802 m²
How Turns per Volt changes with Frequency
| Frequency (input) | Turns per Volt (result) |
|---|---|
| 100 Hz | 4.505 |
| 0.25 kHz | 1.802 |
| 0.5 kHz | 0.9009 |
| 0.75 kHz | 0.6006 |
| 1 kHz | 0.4505 |
| 1.5 kHz | 0.3003 |
| 2 kHz | 0.2252 |
| 4 kHz | 0.1126 |
| 7 kHz | 0.06435 |
| 10 kHz | 0.04505 |
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<p><a href="https://vbatpower.com/formulas/turns-per-volt/">Transformer Turns-per-Volt</a> Calculator by vbatpower.com</p>Frequently asked questions
How do you calculate Transformer Turns-per-Volt?
Use Turns/Volt = 1 / (4.44 × f × Bmax × A). With Frequency 1 kHz, Peak Flux Density 0.5 T, Core Area 10 cm², Turns per Volt works out to 0.4505.
How do you calculate transformer design turns per volt core area 39 cm2 50 hz?
Rearrange for Turns per Volt: with Frequency 50 Hz, Peak Flux Density 10 mT, Core Area 1 cm², Turns per Volt is 4505.
How to calculate turns per volt for ei 48/16 core?
Rearrange for Turns per Volt: with Frequency 1 kHz, Peak Flux Density 0.5 T, Core Area 10 cm², Turns per Volt is 0.4505.
What is the formula for Transformer Turns-per-Volt?
The formula is Turns/Volt = 1 / (4.44 × f × Bmax × A). Turns-per-volt is the practical design figure that tells a transformer winder how many turns to put on each winding per volt of desired output.
How do you find Frequency when you know the other values?
Rearrange for Frequency: with Turns per Volt 0.025, Peak Flux Density 10 G, Core Area 10 mm², Frequency is 0.9009 GHz.
How do you find Peak Flux Density when you know the other values?
Rearrange for Peak Flux Density: with Turns per Volt 0.025, Frequency 5 Hz, Core Area 10 mm², Peak Flux Density is 180200 T.
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