Re: Laptop AC Adapter with fluctuating DC output
- From: NoSpam@xxxxxxxxxxx (Bob Masta)
- Date: Sat, 30 Jun 2007 12:43:45 GMT
On Fri, 29 Jun 2007 19:05:13 -0700, slider123456@xxxxxxxxxx wrote:
I did not test the output under load. I would like to so I can see
what happens but I am not sure what I should use as a load. Using the
laptop is very hard since the motherboard has to come out in order to
have access to the pins for testing. The adapter output is rated for
19.5 volts 6.7 amps. Do you have any suggestion for what I could use
as a load so I can test the adapter
You don't need to draw the full 6.7 amps, just something reasonable.
Even pulling an amp or less will probably be enough to show if the
adapter is shot... at least it was in my case.
The biggest problem is often making connection to the output of the
power adapter. In my case, I just stuffed the leads of the resistor
into the holes of the adapter, with the meter clipped onto the leads.
If you have a power resistor (bigger than 19.5/6.7 = 2.9 ohms but
less than say 20 ohms) you can try that, or wire a bunch of
lesser-wattage resistors together. You won't need to test for more
than a second or so, just enough to get the reading: Low-wattage
resistors may get hot really fast, but you can get a reading just
before you burn your fingers. <g> (And getting hot is a Good Thing,
since it tells you the adapter is at least putting out juice... mine
wasn't.)
Note that when you combining low-wattage resistors to get a
higher power rating, it dosen't matter (to the effective power
rating) whether they are in series or parallel. So 10 x 1 ohm
1/4 watt resistors in series gives 10 ohms at 10*(1/4) = 2.5 watts.
Or 10 x 100 ohms in parallel gives the same thing.
Best regards,
Bob Masta
D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Signal Generator
Science with your sound card!
.
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- Laptop AC Adapter with fluctuating DC output
- From: slider123456
- Re: Laptop AC Adapter with fluctuating DC output
- From: Bob Masta
- Re: Laptop AC Adapter with fluctuating DC output
- From: slider123456
- Laptop AC Adapter with fluctuating DC output
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