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Beginners / Re: AA Ni-MH battery charger output current mA
« Last post by IanB on Today at 01:46:26 pm »
Thinking about different cheap AA Ni-MH 1.2v battery chargers.    two look identical. both have 120v AC input.   different brands yet both have label reads "200mA x 4".  I measure current mA by opening the circuit with a piece of paper between charger and battery then close the circuit with meter probes adjacent to each side of the paper,  but each outputs different mA to each battery depending on 1,2,3,4 batteries charging at same time.  #A  120mA    90mA    72mA    60mA,   #B  60mA   60mA    60mA   60mA.

what is "200mA x 4" supposed to mean?

Whatever the marketing people want it to mean  :)

A more useful number to look at is how many hours it should take to charge a typical battery. If the charger is really charging at 60 mA then a typical 2000 mAh battery would take about 36 hours to charge, which is silly. Nobody would wait that long.

Make and model number of the chargers would be helpful.
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General Chat / Re: Email notifications are broken?
« Last post by gnif on Today at 01:42:23 pm »
I just noticed I'm having this issue... the last notification I received was on 19 April.   :'(

This is known, part of the server move and is being corrected.
See http://www.eevblog.com/forum/news/planned-downtime-2018-04-21-000000-gmt/ and stay posted.
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General Chat / Re: Do people not wire wrap anymore?
« Last post by gnif on Today at 01:41:24 pm »
I never learnt to use wire wrap, but did see examples of it in my dad's electronics junk box when I was a child. I went straight for strip board and kynar wire for prototyping, all soldered. Technically not wire wrap but using the wire :)
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General Chat / Re: Email notifications are broken?
« Last post by geekGee on Today at 01:40:33 pm »
I just noticed I'm having this issue... the last notification I received was on 19 April.   :'(
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Why not use a transformer? It's probably be going to be an expensive one, since you want really high permeability to keep the number of windings on the secondary low ... but it does allow you to drop noise a bit and do common mode rejection without needing a differential amplifier.
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EEVblog Specific / Re: EEVblog #1077 - Dumpster PC Repair
« Last post by Tek_TDS220 on Today at 01:33:26 pm »
Dave is at his best ~13:30 when he puts in the replacement power supply and it works.  I think he went through his whole repertoire of Aussie-isms.  He is educational in many ways.
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EEVblog Specific / Re: EEVblog #1077 - Dumpster PC Repair
« Last post by Stefan Payne on Today at 01:32:48 pm »
Power supply repair attempt on an i7-2600 Dell Optiplex 990 dumpster PC.
An update on previous dumpster PC's.
And the bunker to the rescue.
A couple of things, since you probably don't read Youtube Comments that much:

1. The Formfactor is called TFX, so you could replace it with a "named brand" TFX PSU form like FSP.

2. The Foam is probably Anti Insect foam, that prevents Insects from creeping under the PCB, commiting Suicide and killing the PSU in the process.

3. The Processors aren't that great...
I7-3770 is Ivy Bridge, that one was replaced in 2012 or 2013 by Haswell. the i7-2k and 3k units use the same socket by the way, so you could change them however you want, if you want to.
Anyway, we are talking about something like 6-10 Year old Computers.
The sad thing is that you can use them even today and use it for gaming without any problems. The newest ones aren't that much better (well, at least the 4 core ones)...
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EEVblog Specific / Re: EEVblog #1077 - Dumpster PC Repair
« Last post by wilfred on Today at 01:31:03 pm »
My machine is better than that C2D E7400 power supply doner. But not by much. It must be near its 10 year birthday soon.

Great video, it ticks all the best sayings boxes. Not sure i heard Bobby Dazzler.
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General Chat / Do people not wire wrap anymore?
« Last post by Beamin on Today at 01:27:41 pm »
I know when I was a kid back in the 90's that's how I made everything. Still today I do that. Although I see almost no one doing that on you tube. Also just buying the little tool cost 30.00$ just for one size wire! I remember the tools used to be throw away cheap too not 60$ for the two sizes you need. Is it because now everyone has laser printers and at home PCBs?
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Beginners / Re: AA Ni-MH battery charger output current mA
« Last post by Audioguru on Today at 01:26:33 pm »
Your meter measures current by connecting a resistor in series and measuring the voltage across the resistor. A smart charger sees the battery with too much resistance in it and shows an error.
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