Breaking News
Comments
Newest First | Oldest First | Threaded View
<<   <   Page 2 / 2
David Ashton
User Rank
Blogger
Temperature Meter
David Ashton   2/8/2014 4:13:20 AM
NO RATINGS
Page 3 shows how to make a temperature meter with a cheap DMM.  However it only works from +10 to +125 Degrees C.  Not much good in Canadian winters...

The datasheet for the ICL7106 (which is almost universally used in these meters, along with its lower power sister the ICL7136, shows how to make a temperature meter using an NPN transistor and 3 resistors, a cap and 2 presets.  I've never done this but I know someone who did, I think it will do negative temps as well.  

The LM/TMP35 used above gives an output voltage proportional to degrees C, but the LM335 gives an output proportional to degrees K.  Although this is more difficult to work with, it should be possible to use that and make a degrees C (or F) reading thermometer which does negative temperatures.  You can use the ref pins on the ICL71x6 to provide a stable offset to give a zero reading - as in the ICL7106 datasheet app.

David Ashton
User Rank
Blogger
Fluke Mods
David Ashton   2/7/2014 8:08:08 PM
NO RATINGS
Hi Caleb, thanks, nice collection, there are some smart guys out there.

I have a Fluke 8050 (page 4) - although about 40 years old now, they are a great bench meter but the displays go black after some years - maybe that's why the guy did the mod?.  I was lucky enough to find a replacement one for mine about 20 years ago and since then it has been good, but I'd look at doing something like this if it went wrong again.  I've also seen a mod that replaced the LCD with 7-segment LED displays (and it is referred to in the article you link to)  - I downloaded that as insurance, as I will this one!   I also have a Fluke 8020A - 3-1/2 digit little brother of the 4-1/2 digit 8050A - and had the same problem with the LCD and was also lucky enough to find a replacement.  But you could do a similar mod there.

Incidentally, you refer on page 4 to a "Fluke 8050A Scope" - I think you meant DMM?

Susan Rambo
User Rank
Blogger
Nice hacks
Susan Rambo   2/7/2014 8:05:44 PM
NO RATINGS
Nice hacks to some cheap test tools. Thanks Caleb.

<<   <   Page 2 / 2


Flash Poll
EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Max Maxfield

MSGEQ7-Based DIY Audio Spectrum Analyzer: Testing
Max Maxfield
9 comments
In my previous column on this topic, we discussed the step-by-step construction of the first pass at a MSGEQ7-based DIY audio spectrum analyzer for use in my BADASS Display project. Of ...

Karen Field

June 2014 Cartoon Caption Winner
Karen Field
13 comments
Congratulations to "Wnderer" for submitting the winning caption for our June cartoon, after much heated conversation by our judges, given the plethora of great entries.

Jeremy Cook

Inspection Rejection: Why More Is Less in a Vision System
Jeremy Cook
3 comments
Albert Einstein has been quoted as saying, "Everything should be as simple as possible, but not simpler." I would never claim to have his level of insight -- or such an awesome head of ...

Jeremy Cook

Machine Fixes That Made Me Go 'DUH!'
Jeremy Cook
21 comments
As you can see in my bio at the end of this article, I work as a manufacturing engineer. One of my favorite things that happens on a Friday late in the afternoon is to hear my phone ring ...

Top Comments of the Week
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)