resettable fuse

[Admin]

I found this interesting fuse today that could be useful to everyone.

http://www.sparkfun.com/commerce/product_info.php?products_id=8357

For this model, if your circuit tries to draw more than 500mA of current (if you have a bad short for instance) the PTC would 'trip' (by heating up). The increased resistance (trip state) would only allow 250mA to flow.

250mA may still be enough to hurt some electronics but it's much less than the 3A that the short may have allowed. Removing the short, the PTC 'resets' and allows current up to 500mA to flow again.

For some situations, it might actually allow your robot to continue to partially function to complete an important task despite a serious fault with a particular part. I think Ill buy a few of these . . .

[Qubix]

Sparkfun has some great things (you just can't get anywhere else, breakout boards, cheap serial LCDs), but sometimes their prices can be quite high. (A lot of things went up in price a few months back)

That resettable fuse can be found for less than half the sparkfun price elsewhere.

http://www.mouser.com/search/ProductDetail.aspx?R=RXE025virtualkey65000000virtualkey650-RXE025

Also there is more choice, so you can buy ones with different hold and trip currents which might suit you better.
http://www.mouser.com/search/Refine.aspx?Ne=254016%2b1447464&N=1323038%2b254138&Ns=P_SField&RefType=Header]

[ed1380]

Looks awesome, but like it says letting that 250mA pass might still hurt something.

I've had a bad experiance with sparkfun, since it took them a week to ship something ot me. Digikey FTW