Driving Electromagnetic Coils — Why Current Output Matters More Than Voltage

Driving an electromagnet or coil to produce a target magnetic field comes down to one number: current. Aigtek's ATA-300 and ATA-3000 series are built specifically around delivering high current at low output impedance for exactly this class of application.

Why Current, Not Voltage, Drives Magnetic Field Strength

The magnetic induction intensity produced by an electromagnetic coil is directly proportional to the current passed through it, not the voltage applied. A coil driver's job is therefore to deliver current reliably into what is often a low-impedance, inductive load — which is why these amplifiers are specified with a low 0.1Ω output impedance rather than a high-voltage rating.

ATA-300 vs ATA-3000 — Matching Scale to Requirement

The ATA-300 series is the higher-current, higher-power option for larger coils or stronger field requirements; the ATA-3000 series covers smaller-scale coil driving at a correspondingly lower cost. Within each series, individual models trade off bandwidth against maximum voltage and current — the ATA-318, for example, reaches the full 80A rating but only to 20kHz, while the ATA-315 extends to 150kHz at lower current.

Selecting the Right Model

Start from the coil's required current at your target field strength and frequency, then check which model in the appropriate series meets that current rating within your required bandwidth. Voltage headroom matters too — a highly inductive coil will develop back-EMF proportional to di/dt, so a model with adequate voltage compliance avoids the amplifier hitting its voltage limit before reaching the target current.

Finch Electronic Solutions — Melbourne, Australia
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