Transformer
Two magnetically coupled inductors that transfer energy between circuits while changing voltage and current levels. Used for AC voltage conversion, galvanic isolation, and impedance matching.
Properties
| Property | Description | Default | Range |
|---|---|---|---|
| Turns ratio | Primary-to-secondary turns ratio (n:1) | 10:1 | 0.01:1 – 1 000:1 |
| Primary voltage | Rated primary winding voltage (V) | 230 V | 1 V – 10 000 V |
| Rated power | Maximum power the core can transfer (VA) | 50 VA | 1 VA – 100 000 VA |
| Coupling coefficient | Magnetic coupling efficiency (0–1, where 1 is ideal) | 0.99 | 0.5 – 1.0 |
Simulation behavior
Secondary voltage = primary voltage / turns ratio. Secondary current = primary current × turns ratio (conservation of power). Leakage inductance and core losses are modeled implicitly through the coupling coefficient — a value below 1 introduces magnetizing current and reduces the effective secondary voltage under load.
If power transferred through the core exceeds rated power, the transformer fails (open-circuit on both windings).
The transformer only operates with AC — a DC input produces no secondary output because there is no changing magnetic flux.
Tips
- A turns ratio of 1:1 creates a galvanically isolated version of the input signal — useful for eliminating ground loops between two circuits without changing voltage.
- To step down 230 V AC to 12 V AC, set primary voltage to 230 V and turns ratio to approximately 19:1.
- Keep the coupling coefficient at 0.99 for an ideal transformer model. Reduce it to 0.85–0.90 to model a loosely coupled or air-core transformer with significant leakage.