Relay Driver circuit (transients problem?)

[BlackHelicopter]

Hi I'm driving a relay using a FET using the circuit shown. And parts keep blowing up. What kind of transient effects are likely to occur here and what can be done about it? Also, I see a lot of BJT circuits with a reverse diode in parallel with them when driving relays (diode is connected between Collect and Emitter) what does that diode do exactly and why is it there? Do I need one at the output of the comparator? (open collector?)


Thank you!

 

[cameo_2007]

the FET is blowing up?

 

[NishantSood]

That Diode Exactly Absorbs the Current that is SHOT back by the Relay when it Actually gets OFF and saves your BJT Circuits NPN or PNP Transistor from Getting BLOWN up with Surprise Electrical SHOT.