Appendix D: Operating Characteristics
Logical Errors
If you attempt a calculation containing a logical error—say division by zero—an error signal is triggered and a blinking display appears. To reset, press CLx . The following are examples of logical errors:
  Division by zero
  yx where y ≤ 0
  Date/day calculations where (a) the range is exceeded, (b) a date entered doesn’t exist, (c) date entry conventions are not followed
Scientific Notation
Answers greater than 1010 (9,999,999,999 + 1) are displayed in scientific notation-an abbreviated form of the number showing an exponent of 10 in the last two character positions.
If a number is displayed in scientific notation and has a negative exponent, pressing CHS will, in addition to changing the sign of the number, alter the display of the exponent. Although the exponent is not displayed properly, it is correct internally and the number in the display may be used in a normal manner for further calculations. However, if you wish, you can produce the correct display before proceeding by pressing x y x y
Environmental Considerations
Mode Temperature °C Temperature °F
0°C to + 50°C
+10°C to +40°C
40°C to +55°C
32°F to 122°F
50°F to 104°F
40°F to 131°F
Battery Operation
Use only the HP Rechargeable Battery Pack, Model 8200 I A, which has been tested and is warranted for one year. The battery provides three to five hours of continuous operation. By turning off the power when the calculator is not in use, the HP-80 battery power will last easily throughout a normal working day. Note that it is normal for the battery charger to be warm to the touch when in use.
All decimal points light in the display when 2 to 5 minutes of operation time remain in the battery pack. Even when all decimal points are turned on, the true decimal position is known because an entire digit position is allocated to it.