the need for matched fets
Well if the fets are matched but the resistors (and possibly caps) aren't matched, why is there a need to matched fets?
non-matching resistors will have different voltages across it.
Maybe using matched fets somehow balances the whole circuit even if the resistors/caps aren't matched?
Very simple math. Resistors have usually 1% tolerance, often 0.1 %, and this is the maximum (garanteed) tolerance. Some caps have 1% nominal tolerance caps but I measured caps with 5% nominal tolerance that actually had tolerances well below 1%.
Fets by comparison have much higher tolerances for some of their critical parameters, more like 10 % and for some parameters even more (Idss of jfets more than 100 %). Go figure.
|All times are GMT. The time now is 12:18 PM.|
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2013 DragonByte Technologies Ltd.
Copyright ©1999-2013 diyAudio