KSD-01F D85C TO-220 (2leg) Code: 80913654

The KSD-01F D85C (often written as D85 or 85°C) is a miniature, bimetallic temperature-sensing switch. It features a Normally Closed (NC) contact configuration, meaning the internal circuit remains connected until the sensor’s temperature reaches 85°C, at which point it opens to cut off power and protect systems from overheating.

Key Specifications

• Action Type:Normally Closed (NC)
• Trip/Action Temperature:85°C ± 5°C
• Contact Rating:Typically 1.5A at 220VAC / 3A at 24VDC
• Package Form:TO-220 (metal base plate for excellent heat transfer)
• Operating Ambient Range:-55°C to +160°C
• Contact Resistance:≤ 50 mΩ
• Dimensions:7 × 10.2 × 4.7 mm ]

How It Works

The switch contains a bimetallic strip that is calibrated to react to a specific temperature. As the surrounding environment (or the heatsink it is mounted on) reaches 85°C, the bimetal strip deforms, instantly breaking the contact. Once the temperature drops by about 5°C, the strip snaps back into place, re-closing the circuit.

Typical Applications

Because of its small TO-220 footprint, it is highly suitable for space-constrained Printed Circuit Boards (PCBs). Common uses include:

• Overheat protection for power supplies, inverter welding machines, and HVAC equipment.
• Temperature regulation in computer peripherals and microcontrollers.
• Safety cut-offs in various household and industrial appliances.