The BK250-200-DZ by Yageo is a polyfuse, also known as a PTC (positive temperature coefficient) resettable fuse, through-hole component which meets RoHS compliance standards. It is used as an over-current protection device in circuits, where it will react to an abnormal increase in current by raising its own resistant. When the current falls back to normal level, the fuse will reset itself. This part is rated for 200 volts with a hold current of 250mA, and a trip current of 500mA. It is suitable for high-frequency applications such as automotive systems, computer peripherals, LED lighting, and consumer electronics. The fuse comes in a 0805 type package and has a low minimum resistance of 5 ohms.