Re: LZ: Re: Batteries
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Re: LZ: Re: Batteries
TGaArdvark@aol.com wrote:
> The AAA batteries are always used unless they cannot supply the power
> demands
> from the calculator. Even when the calculator is off, the AAA
> batteries are
> used. If the batteries are removed or run out, the calculator will
> automatically switch to the lithium battery. This is hard-wired to the
>
> circuit board. The calculator itself never involves itself with the
> power
> sources; the printed circuit board checks the batteries and changes
> sources.
> If the calculator is on when a battery is removed, the circuit board
> will
> still jump to the lithium battery. The problem is that the lithium
> battery is
> nowhere near powerful enough to run the entire calculator (duh). You
> would
> think that this will drain the lithium bttery when a battery is
> removed while
> the calculator is on. The actual drain on it is minimal, though. As
> soon as
> the calculator has less than the power needed to function, it stops
> operation
> completely. The fact that the calculator COMPLETELY shut down is what
> erased
> the memory. The calculator is always active to some degree (waiting
> for the
> on key, which can be run by the lithium battery). It's when the
> calculator
> shuts down complelely that you lose your memory.
>
> NOTE: This is based on my personal research and experimentation. It
> may not
> be 100% accurate, but it's close.
hmm..
The way I understand backup batteries in general, they just keep 5v on
the
RAM chip (at a very low trickle, like .01 ma) so the chip won't lose its
contents.
I don't know if this is different in the TI calc or not (need to
experiment more), but
I know that's how it works in pinball machines and such (I work on
these.)
--Paul
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