SCK20200 20 ohm 4A NTC Thermistor - Limit Inrush Current

SCK20200 NTC Thermistor 20Ω 4A – Inrush Current Limiter for Mining PSU Protection

The SCK20200 is a negative temperature coefficient thermistor with a cold resistance of 20Ω, rated at 4A, in a 20mm radial-lead disc package with resin coating. It limits inrush current on the AC input stage of mining power supplies — at power-on, the 20Ω resistance absorbs the surge into the bulk capacitors, then self-heats and drops to near-zero resistance for normal operation. Operating range -40°C to +200°C, RoHS and halogen-free certified.

Why NTC Thermistors Fail in Mining PSUs

Every power-on cycle forces the NTC to absorb inrush energy. In mining environments with frequent power cycling — maintenance, outages, rolling restarts — the cumulative thermal stress degrades the device. A failed NTC either cracks open (PSU won't start) or shorts (no inrush protection, stressing the bridge rectifier and bulk caps on every cycle). Replacing a failed NTC is a low-cost repair that prevents cascading damage to more expensive downstream components.

Replacement Procedure

Disconnect mains and discharge bulk capacitors. Locate the SCK20200 on the input filter board near the AC inlet — a large disc with two radial leads. Desolder, remove, install the new thermistor through the same holes. Solder, trim leads, reassemble and verify normal startup with controlled inrush.

SCK20200 Thermistor Specifications

Related NTC Thermistors & PSU Input Protection

• NTC 20D-20 Power Thermistor 20Ω 250W – PSU Repair
• MF72 10D15 NTC Thermistor – APW3 PSU Repair
• NTC 16D-20 Thermistor – PSU Repair
• NTC 5D-15 Thermistor – PSU Repair

Repairing PSU input stages? Contact us at contact@lys-sz.com for NTC thermistors, varistors and protection components.

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