DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: { antonio } on May 06, 2004, 10:22:47 AM

Title: how do i match transistor
Post by: { antonio } on May 06, 2004, 10:22:47 AM
how do i go about matching transistors?

can i use the hfe input on my multimeter?

thanks in advance.
Title: how do i match transistor
Post by: Paul Marossy on May 06, 2004, 10:33:39 AM
Yep. That's all you have to do if they are just regular transistors. With germanium transistors, there is a different approach to measuring them to find the true gain since they are leaky and sensitive devices. That can be found at www.geofex.com

JFETs are a whole different story. You can also read about that at the link above.
Title: how do i match transistor
Post by: Mark Hammer on May 06, 2004, 11:28:45 AM
Yes and no.

For instance, when a "matched pair" are used for something like a current mirror (yeah, like I know what that's all about!) on a mic preamp or a high-quality VCA, apparently they need to be matched for more than mere hfe.  This is why there are matched pairs in a single package like the 2SC1583, 2SC798, the MAT-01/02/04, the SSM2210, etc., although these are also pairs in a package for reasons of temperature as well.

In other instances, things are exactly as described by Paul, and basically all you're looking for are two transistors that "push" just as hard as each other when asked to do so.
Title: thanks.
Post by: { antonio } on May 06, 2004, 09:53:56 PM
thank you so much.

antonio.
Title: how do i match transistor
Post by: keninverse on May 07, 2004, 11:14:37 AM
Isn't it more imortant to match for voltage drop?