SACE Stage 2 Physics — Electricity & Magnetism 2.5

Transformer

Two coils share a soft-iron core. An alternating voltage on the input coil drives an alternating flux through the core, and that changing flux induces an EMF in every output turn. Because each turn sees the same dΦ/dt, the voltages are simply in the ratio of the turn counts: V_output / V_input = N_output / N_input. Drag the sliders to step the voltage up or down.

Input voltage V_input (RMS)

Input turns N_input

turns

Output turns N_output

turns

Quick presets

Drive

V_output / V_input = N_output / N_input

Turns ratio N_output/N_input—

Input V_input—

Output V_output—

Mode—

Ideal transformer assumed: all input flux links the output coil, and there are no winding-resistance, hysteresis or eddy-current losses, so V_inputI_input = V_outputI_output.

Soft-iron core couples the coils — the same alternating flux passes through every turn.