Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: Macintosh batteries (no physics)

"Wilson J. Gonzalez-Espada" wrote:

I always thought that an electric appliance was designed
for 4.5 V (for example) AND a particular current. That is
why I thought I could not connect a car battery on a 12V
handheld flashlight.

Nearly any dc gadget designed for 12 V dc will work
from a car battery. The only exception would be a device
which counts on a specific value of the so-called "internal
resistance" of the battery, r, for its normal operation. A
handheld flashlight works normally when its own R is much
larger than r. It does not care if r=0.01 or 0.001 ohms

But the effect of making a short does depend on r; a new
car battery may give you 100 A or more.