<p style="text-align: left;">Drain Voltage vs Drain-Source Voltage. Difference?<br><br><br>Posted by fourierpwn on 13 Dec, 2018 11:21<br>I think the title is pretty self-explanatory. <br><br>For any FET or FET-like (MESFET, JFET, HEMT, etc) device, is Vd the same as Vds?<br><br>I was once told that they're not the same thing but I do not understand why. I would say that this has to do with the point of reference but to say that Vd is not the same as Vds then what is Vd referenced to? <br><br>If we say that it is referenced to some other terminal, then it would become VdX where X is gate (Vdg), body (Vdb), source (Vds). Right?<br><br>Perhaps this is something which is only considered on the intrinsic level? :-//<br><br><br>#1 Reply<br><br>Posted by mikerj on 13 Dec, 2018 11:30<br>You are correct, this is simply down to the reference voltage you use. Vd would typically mean the drain voltage w.r.t 0v, but the source terminal may not be tied to 0v so Vds would be different.<br><br><br>#2 Reply<br><br>Posted by T3sl4co1l on 13 Dec, 2018 21:00<br>Source is generally considered the common terminal. But do check if they're referring to a standard test circuit/fixture that they're using, and if the source voltage is nonzero, that will matter!<br><br>Speaking of RF types, mind that Vds(max) is usually rated as the DC figure, while assuming an inductive load (RFC, bias tee, whatever) in a conventional common-source amplifier -- the peak rating (beyond which breakdown can be expected) may be 2 or 3 times higher!<br><br>Or maybe it's not. The only way to tell is to waste $50+ by blowing one up. :palm: RF parts...<br><br>Tim<br>There was an error while thanking<br>Thanking...<br>Go to page: <br>1<br>Powered by SMFPacks Advanced Attachments Uploader Mod</p>
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