Asahi US-802 Miniature Thermal Switches

The Asahi US-802 miniature thermal switch is a slim, space-saving snap-action device to help you control temperature in the tightest of spaces.  Originally designed in a TO-220 package for mounting onto heat-sinks to help monitor power components, the US-802 can be used wherever there is a potential overheat situation in a small space.

The US-802 is available with factory preset calibrations from 40°C up to 120°C with a ±5K calibration tolerance.  The standard temperature differential (or hysteresis) is 15K with a ±7K reset tolerance.  This is the same right across the temperature range and shows the precision to which Asahi products are manufactured.

The contacts (both break-on rise and make-on-rise are available) are capable of switching 100,000 cycles at 20mA/5VDC or 30,000 cycles at 1A/125VAC (or 48VDC).  The stiff lead-wires have a standard 5.08mm pitch to assist with p.c.b. mounting.



  • Heat-sink sensing
  • Power component monitoring
  • Power supplies
  • Air-sensing on p.c.b.s


  • TO-220 case, single M3 screw mount
  • Calibrations from 40°C to 120°C in 5K increments
  • Break-on-rise and make-on-rise contact operation
  • 100k cycles at 20mA/5VDC (30k cycles at 1A/125VAC)
  • C-UL and VDE approvals
Slim space-saving snap-action thermostat. TO-220 case. UK stock from ATC Semitec