WP 34S and 31S bugs and fixes

[grsbanks]

(02-04-2017 08:12 AM)Paul Dale Wrote:  purchase quality brand name batteries, rather than eBay cheapies.

This is something that people often don't bother considering.

Battery life isn't the only thing that varies between different battery manufacturers and the quality of their products. Another factor that sensitive electronic devices (such as calculators running at low voltages!) can have an adverse reaction to is the internal resistance of the battery.

Cheapies often have a higher internal resistance than batteries of an established brand because the manufacturers have cut corners in the manufacturing process in order to cut costs. What is the effect of this? It means that the voltage being output by the battery when under load (eg. when performing a computationally intensive calculation) drops more than with a quality battery. This makes them look to the calculator like they're going flat when they're not yet.

Another side effect of this is a direct result of Joule's law: P=UI; U=RI => P=RI²

The power dissipated (in the form of heat) by a resistor is proportional to the resistance (in Ohms) for a given intensity (current, in amperes).

More resistance = more voltage drop and more heat dissipated. Not good for a calculator.

Buy good batteries!