Amprobe AM91RS Digital-Multimeter - Manual (Page 10)

9
Hz, % + Hz functions
Defaults at Hz. Press SELECT button momentarily to select % + Hz.
Note: Unlike the AC + Hz function, this high resolution Hz function is set at the highest
input sensitivity to measure digital type electronic signals.
Backlighted display
Press the SELECT button for 1 second or more to turn on and off the display backlight
function. The backlight will also be turned off automatically after 42 seconds to extend
battery life.