How to calculate the power dissipated in Mosfet?

[Okada]

Re: How to calculate power dessipated in Mosfet ?

How about this ?

http://www.tek.com/oscilloscope/tbs1000-digital-storage-oscilloscope

The TBS1000B

http://www.tektronixindia.co/?utm_s...XhzMNyI_Fsx5MENXC271aCQ5AMRC9NFP9XBoC-pTw_wcB

 

[Warpspeed]

Re: How to calculate power dessipated in Mosfet ?

That does have a multiply function.

Current through the mosfet on one channel from a current probe.
Voltage across the mosfet on the other channel.
Third "maths" channel will display instantaneous power.

What you will see is fairly steady power during the conduction period, with a very narrow power spike at both turn on and turn off. That should give you a pretty good idea of total dissipation.

 

[Okada]

Re: How to calculate power dessipated in Mosfet ?

Ok. I will buy TBS100B. Earlier I was planning to buy Rigol (maybe 1053Z/E).

 

[Warpspeed]

Re: How to calculate power dessipated in Mosfet ?

There is probably not much to choose between the two brands, both are excellent oscilloscopes.

 

[Okada]

Re: How to calculate power dessipated in Mosfet ?

Sorry, Actually I was planning to buy DS1054Z

https://www.batronix.com/shop/oscilloscopes/Rigol-DS1054Z.html

Which is better ? TBS1000B or DS1054Z ?

 

[dick_freebird]

Re: How to calculate power dessipated in Mosfet ?

Now you seem to have taken a great interest in selecting
the "best" 'scope, but I think that with a sane switching
frequency almost any will do - a 100MHz probe is about all
you can find standard anyway, so what good is more than
200MHz channel BW going to do you, other than for true
50-ohm direct connection work? I would suggest going for
4 channels - 2 is a bare minimum for anything useful and
with a bridge style converter there's plenty of things that
want looking-at all at once.

Now broaden your thinking about test gear. For example
you are very concerned about power dissipation and yet
not once have you mentioned a thermocouple and the
meter to read it. These are cheap on eBay and you could
so easily instrument up all 4 FETs and read Tcase directly
while slowly increasing the load current (easier than this
thread has been, at getting the answer you originally
wanted, surely). Now think about what other instruments
might make your designing easier, safer, more effective.
Current probes? Isolated voltage probing capability that
can work across the flying high side voltage?

Don't blow it all on the "best" 'scope when "perfectly
adequate" plus "sure would help" could be had for the
same (presumably finite) funds. Sure, go for a little bit
of "future proof". But a Chevy with a trunk full of tools
you need, beats a Cadillac that doesn't get you all the
way there.