> I understand the amps.. i understand the max volts.. I assume the > resistance is another way of saying saturated voltage drop.. > > what I don't understand is the watts. > > Like this: if this device can really switch 15A @ 100V, that's 1500W, > not 60 - or are they saying it can _dissipate_ 60W? I just flat out > don't beleive that... > > S. > Yup it power dissapation. I have Igbt in to-247 cases that will dissapate 500 watts and Igbt modules that will dissapate 4200 watts while switching 400 amps of 1200 volts. Not bad switch 1500 loose 60, that's a pretty fair deal. Oh yea Fets is RsDon, calculate as a resistor I2r. Igbt are straight voltage drop amps times Vsat. These are DC ratings. Swithing losses are a whole nother ballgame.