Question for Eric, or Reg

[Kev]

Hi,
It appears that Rob's (RKC) Goldquest has a faulty sampling FET.
I will replace both, but I'm wondering what's the best way to match
them. I've searched the net, and experimented with the diode test
function on one DMM while measuring the resistance on another.

I'm wondering, if it's not a trade secret, what method you use Eric, or
Reg to closely match a pair.

Thank you & Regards
Kev.

 

[Eric Foster]

Hi Kev,

Basically, it is the ON resistances that need to be matched. This is related to the gate turn on voltage, which is what I measure on a home built tester. Easiest thing is for me to post you a matched pair. Send a private message or email to me with your postal address.

Eric.

 

[Kev]

Thanks for the offer Eric, but I don't want to waste anymore of your precious time. I just thought there may have been an easy way. I'll breadboard a jig such as described in the datasheet for observing dynamic Rds, I confess I'm feeling a bit lazy these days.

Best regards.
Kev.

 

[bbsailor]

Kev,

Here is a link to a test setup to match FETs.
http://www.geofex.com/Article_Folders/fetmatch/fetmatch.htm

bbsailor

 

[Kev]

Thanks bbsailor,
Excellant info, I've filed that away for safe keeping, it tells me everything I need to know. I wonder how many yahoo search results I'd have needed to wade through before I found that one? This forum and ones like it are the real goldmine, and those who share this knowledge are the real gold nuggets.

Regards
Kev.