Power Meter Operation
Battery Operation (Option 001)
2-4 Agilent E4419B User’s Guide
Running time can be increased by operating the power meter with the 
display backlight turned off (see “Backlight”, on page 2-4 ).
Figure 2-1:  Battery Status
When the power meter is running on battery power and there are less 
than 10 minutes of run-time remaining, the message “Battery Low” 
appears at the top of the screen. In addition, a pop up window appears 
every minute with the message “Battery Power Low”.
Charging Times
The battery charges automatically when the power meter is connected to 
an ac source. From an empty state the battery is fully charged in less than 
2 hours. After approximately 50 minutes the battery has enough charge to 
enable 1 hour of operation with the backlight on. After approximately 35 
minutes the battery has enough charge to enable 1 hour of operation with 
the backlight off.
Backlight
When you are operating the power meter under battery power you can 
turn the display backlight off or on, or set it to timed mode. In timed mode 
the display backlight turns off 10 minutes after the last key press - the 
display can be turned on again by pressing any key.
Working with the backlight off reduces the drain on the battery and 
increases the operating time available by approximately 50%. The display 
can be comfortably read in ambient daylight with the backlight off.
HP4402.book  Page 4  Thursday, November 30, 2000  1:39 PM