Re: Resistors waste energy WAS:ATM DIY LED Flashlight Conversion

[Gary Seronik <gseronik@direct.ca>]

At 01:11 PM 5/28/97 -0400, you wrote:
>Malte:
>> If you have a Voltage supply of 3 V and a voltage drop of 1.6V at the
>> LED, then you have a voltage drop of 1.4 V at the resistor.
>
>Ok, try this: take a 1000 volt battery.  Then take a ten peta ohm resistor.
> Put it across the battery (i.e. dead short, nothing else in the circuit). 
>Your energy waste will be 0.
>
>Why?  There's no current.

Actually, current in this case would be close to infinite.  If you want no
(zero) current you would need an open cct., that is a resistor with an a
resistance of near infinity.

In reality, if you did this, the battery's internal resistance would be the
current limiting factor and would try to dissipate the energy by heating up
and probably exploding.  Kids, don't try this at home.

Regards,
Gary