Home     Contact     Projects     Experiments     Circuits     Theory     BLOG     PIC Tutorials     Time for Science     RSS     Terms of services     Privacy policy  
   
 Home      Projects     Experiments     Circuits     Theory     BLOG     PIC Tutorials     Time for Science   


<< Back to INDEX

Simple hFE Adapter For Cheap DMMs [Project]
posted January 29 2014 3:49.58 by spic0m




Kerry D. Wong made this simple hack to a cheap digital multimeter.

"Getting a rough measurement of the transistor hFE's is useful when designing analog circuits. Unfortunately, only the lower end DMMs nowadays offer such functionality as it is becoming less and less useful to measure transistor hFEs in a world that is dominated by digital circuitry. Also hFE varies in different biasing situations and the hFE measurements on these cheap DMMs are typically done with a fixed base current (approximately 10 ľA) in DC mode. But even with these limitations, hFE measurements can still be quite useful.

One of the biggest gripe I have over the hFE sockets on these cheap DMMs is that they are extremely difficult to use. They are mostly suited for transistors in TO-92 packaging. With some luck you can probably measure transistors in larger packages (e.g. TO-126). But if you are trying to measure hFEs for even larger transistors (e.g. in TO-220 or TO-247), you are out of luck.

My solution here is to solder on an external socket so that I could attach mini-grabbers when I need to measure transistors that do not fit in the TO-92 socket. The picture below shows this approach. Basically, I just routed the EBC pins for both the NPN and PNP sides out to a 6-pin socket. The wires on the red zip tie side are for NPN transistors and the wires on the yellow zip tie side are for PNP transistors. To make these clips easily identifiable, I also color coded the wires and clips: black for emitter, blue for base and red for collector. Alternatively, you could just use one set of clips and use a 3PDT switch to switch between NPN and PNP measurements."




[Link: Kerry D. Wong]
 
Share



You might also like...


Why we raise our right hand when taking an oath? [Random Knowledge #29]

NASA's Deep Space Network: 50 years of Interplanetary WiFi [Space]

Bitrot and atomic COWs: Inside 'next-gen' filesystems [Tech Article]

Build an RC Blimp for less than $13 [Project]

I Will Fix That! #10 [4 Photos]

Amazing art with stones [Photos]

Groundbreaking Gesture-Control System On Its Way Into Our Smartphones [Technology]

Function Generator using ICL8038 [Project]


<< Back to INDEX



Comments

  Name

  Email (shall not be published)

  Website

Notify me of new posts via email


Write your comments below:
BEFORE you post a comment:You are welcome to comment for corrections and suggestions on this page. But if you have questions please use the forum instead to post it. Thank you.


      

No comment yet...

Be the first to comment on this page!












 Contact     Forum     Projects     Experiments     Circuits     Theory     BLOG     PIC Tutorials     Time for Science     RSS   

Site design: Giorgos Lazaridis
© Copyright 2008
Please read the Terms of services and the Privacy policy