LM317 power dissipation

[bigboss59400]

Hello,

I want to know how we can calculate the power dissipation of the LM317, I saw in the datasheet the ratio temperature/W, however how to calculate the power takes by the LM ? Is it something like Vin*Currentset ? (In my case it will be something like 1.25*8=10W)

Is it a good idea to power the LM317 with 2 li ion cells at 1.25A ?

Thanks

 

[Cyparagon]

(Battery voltage - diode voltage) * operating current = power dissipated

 

[bigboss59400]

Thanks a lot man, that's help me a lot to know if I have to put a heatsink to this driver