From: James (orialv21_at_mindspring.com)
Date: Wed Jul 21 1999 - 19:12:33 EDT
Bill and Juan-Carlos,
The point I was trying to make is that "more amp is not necessary better than less" as Bill have indicated in his original posting. And the reason is because it causes thermal breakdown.
Thermal breakdown occurs when there is an excess amount of current across a cross area of a conducting medium per unit second.
In semiconductor language, what this means is that the current causes an the rate of charge separation is faster than the rate of recombination.
Above all, the point is that "more amp is not necessary better," a concept that all devices or electrical engineers should know. Like what Juan-Carlos said, assuming resistance is constant, then the voltage across the device determines the amp passing through it.
Thanks
James
----- Original Message -----
From: Juan-Carlos Lerman
To: James ; thinkpad_at_cs.utk.edu
Sent: Wednesday, July 21, 1999 3:59 PM
Subject: Re: Interesting TP accessory prices
orialy21 said:
> In most cases, more amp is not better because it could
> lead to thermal breakdown unless your device is
> designed to run on reverse bias - as some diodes are.
Can you explain what do you really mean and how
does it relate to the problem?
It's my (poor) understanding that the power adaptor
is a constant *voltage* source, not a constant
*current* source.
In consequence the amperage drawn from it is only
dependent on the resistance of the device connected
to the output of the power supply.
And this follows Ohm's law:
current(in amps) = voltage(in volts) / resistance(in ohms)
In other words the adaptor will supply the device
with any amperage as required by the device, up
to the maximum value indicated on the label. Above
that, expect thermal breakdown.
JC
===
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