Schematic symbol

[alex-sh]

Hello,


I have come across this symbol in the schematic, which I believe it a thermistor.
However, I do not understand 100ma and a symbol right next to it.
Could somebody please enlighten me what this means?

Many thanks
Alex

[Zero999]

It is a type of thermistor. It's a PTC resistor used for overcurrent protection. It performs the function of a self-resetting fuse. Its temperature rises, as the current increases, causing its resistance to increase and further heating towards the tripping point, when its temperature and resistance rapidly rises, causing it to limit the current to a very low level. When the current is interrupted and it's left to cool, its resistance drops and it's ready to go again.

[alex-sh]

Funny enough I have a few PTC thermistors and used them to protect the circuitries from overcurrents, but I have never seen such symbol in a schematic. Typically I see the one attached for PTC thermistors.

Many thanks for your help Zero999!

[WildMOSFET]

That symbol (with the "-") is also used for the NTCs, they are always thermistors which, however, work in contrast to PTCs: as the current increases, they reduce their resistance.