In a message dated 8/18/2002 10:46:28 PM Eastern Daylight Time,
[EMAIL PROTECTED] writes:
> No ~ too much voltage.
> 1.55 and 1.35 is voltage, not current.
>
> Further more, a load "draws" current, depending on the resistance of
> the circuit.
> Lower the resistance, the load will draw less.
> If you have a sufficiently robust power supply, it will deliver
> whatever current your load requires.
> No more, no less.
>
Keith , good thought but not so !!! Its the excess CURRENT thats
destructive..Lets give the Spotmatic meter a 10 ohm fixed resistance
just for example sake:
by the formula E = l x R (E=volts, I = current , R=resistance)
when E = 1.55 1.55 = l x 10 so l = 1.55/10 = 155 milliamps
when E = 1.35v 1.35 = l x 10 so l = 1.35/10 = 135 milliamps
By using the higher voltage battery you are forcing the fixed resistance
(in this case the Spotty meter) to dissipate MORE current. Also be
careful of your "robust power supply". If you plug your 110V shaver into
a 220V supply,by your theory it will draw only the current it needs.
NOT SO ! The 220V will force twice the current thru its resistance
and burn it out in short order !!
Be Careful: you state " lower the resistance and the load draws less "
Its just the opposite: Lower the resistance and the load draws MORE.
A toaster has very LOW resistance so draws LOTS of current.
A nite-lite has HIGH resistance so draws VERY LITTLE current..
I am very pleased to hear the Spotmatic-F has a sophisticated
regulator. When I began studying electronics in the early 70's
DC voltage regulation was crude at best, usually done with voltage
dropping resistors that ate batteries by dissipating the excess
voltage as heat....
Regards,
Bob
(by the way, the 10 ohm Spotty value is for example only, I dont know
the actual value)
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