Keysight Technologies U1190A Serie Guide Rapide page 9

Non-contact voltage detector (Vsense)
Voltage source
AC
3
2
1
4
If the presence of AC voltage is sensed, the clamp
meter's beeper will sound.
Press to change the Vsense sensitivity from
Hi.SE (high sensitivity) to Lo.SE (low sensitivity)
and vice versa.
Voltage could still be present even if there is no alert
WARNING
indication. Never touch live voltages or conductors
without the necessary insulation protection.
Keysight U1190A Series Quick Start Guide 9