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From: Jeff Liebermann <jeffl@cruzio.com>
Newsgroups: sci.electronics.design
Subject: Re: Extech EX410A  DVM  Don't Buy
Date: Fri, 04 Oct 2024 16:07:24 -0700
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On Thu, 03 Oct 2024 14:46:46 -0700, john larkin <jl@glen--canyon.com>
wrote:

>Extech EX410A  DVM  Don't Buy
>
>The auto power off is incredibly stupid. I'm going to throw mine away
>and get something usable.

What don't you like about the auto power off feature in the EX410A?

EX410:
<https://www.flir.com/products/ex410a/>

I have two Extech EX470 DMM's:
<https://www.flir.com/products/ex470a>
Presumably, the auto power off function is similar.

I've had both DMM's for over 10 years and use them often.  I've had no
difficulties except with various 9V batteries.  I got tired of
replacing them.  Over the last 5 or so years, I've experimented with
two types of rechargeable Li-Ion 9V batteries.  

The ones without an internal battery charger had self-discharge
problems:
<https://www.ebay.com/itm/304501384792>
They work, but I wouldn't recommend them.

The batteries I'm using now, which have a built in charger, are
better:
<https://www.ebay.com/itm/386563315011>

If your complaint about the auto power off feature involves some
leakage current when the auto power off feature has turned off, these
batteries might help.  

I just measured the battery drains in my Extech EX470.
  Time to power off:  30 mins
  Operating battery current:  5.4 ma
  Power off after timeout:  0.02 ma
  Power off using rotary switch: <0.01 ma

I also have a Uni-T UT210E.  
<https://meters.uni-trend.com/product/ut210-series/>
I bought it for automotive use because of the "clamp on" DC Ammeter
feature.  3 DC scales (2, 20, 100 Amps DC) using a hall effect device.
It's sensitive to nearby metal objects at <1A DC.  Switching from
between AC and DC is not logical.  When switching ranges, it also
switches from DC -> AC.  When using the hall effect ammeter, resetting
to zero has to be done fairly often.  It uses two AAA alkaline cells.
NiMH will barely work due to low voltage.  Li-Ion AAA are available
but I haven't tried any (yet):
<https://www.xtar.cc/aa-aaa-battery.html>
<https://www.ebay.com/itm/364640309348>
Otherwise, I like Uni-T.

Also, some hacking is possible:
<https://www.eevblog.com/forum/testgear/a-look-at-the-uni-t-ut210e/>




-- 
Jeff Liebermann                 jeffl@cruzio.com
PO Box 272      http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann      AE6KS    831-336-2558