Linear AC/DC

What to look for

• Output ripple. Linear regulation typically delivers <1 mV ripple, an order of magnitude better than an equivalent SMPS. Critical for audio pre-amps, low-signal measurement and RF.
• Radiated EMI. No high-frequency switching means no switching harmonics — ideal for co-located sensitive electronics.
• Size and heat. Expect ~50% efficiency and a heavier chassis. Allow ventilation clearance around the enclosure.
• Regulation type. Series-pass linear regulators hold output volts tightly against line and load; shunt regulators are simpler but only suit fixed loads.

Frequently asked questions

Why choose a linear supply over a switch-mode?

Linear supplies produce far lower output ripple and radiated EMI than switch-mode. That matters for audio, medical, RF, precision measurement and instrumentation — anywhere a few millivolts of switching noise would degrade signal quality or measurement accuracy.

How efficient are linear power supplies?

Typically 40–60% efficient — the balance of input power is dissipated as heat in the pass transistor. Modern SMPS units reach 85–92% but at the cost of higher switching noise.

Are linear supplies still made and stocked?

Yes. Pulsar Developments holds a full UK stock of Mascot linear AC/DC adaptors specifically for applications where switching noise is unacceptable. Same-day dispatch on stocked models.

Can I replace a linear supply with a switch-mode?

Only if the load tolerates switching residuals. For audio pre-amps, medical monitoring, RF front-ends and precision measurement the answer is usually no — stay with a linear supply.