Brymen BM252 User Manual page 7

6
WARNING:
AutoCheck mode input impedance increases abruptly from initial 2.5kΩ to a few hundred kΩ's on
TM
high voltage hard signals. "LoZ" displays on the LCD to remind the users of being in such low
impedance mode. Peak initial load current, while probing 1000VAC for example, can be up to
566mA (1000V x 1.414 / 2.5kΩ), decreasing abruptly to approx. 3.8mA (1000V x 1.414 / 375kΩ)
within a fraction of a second. Do not use AutoCheck mode on circuits that could be damaged by
TM
such low input impedance. Instead, use rotary selector or high input impedance voltage modes
to minimize loading for such circuits.
DCV, ACV, & Line Frequency functions
Press the Hz push-button for one second or more to activate or to exit Hz.
DCV ACV
Hz
J A C K J A C K J A C K
JA C K J A C K J A C K
! ! !
Note:
*Input sensitivity varies automatically with function range selected before activating the Hz function.
6V function range has the highest and the 1000V range has the lowest. It is recommended to first
measure the signal voltage (or current) level then activate the Hz function in that voltage (or current)
range to automatically set the most appropriate trigger level. You can also press the RANGE button
momentarily to select another trigger level manually. If the Hz reading becomes unstable, select
lower sensitivity to avoid electrical noise. If the reading shows zero, select higher sensitivity.
*Number of Bar-graph pointer is used to indicate input range (sensitivity) selected. 1/2/3/4 pointers
indicate 6/60/600/1000V, 6/10/-/-A, 60/600/-/-mA or 600/6000/-/-uA is selected in corresponding V,
A, mA or uA function respectively. ( "-" means range not available)
*The Hz of mV function is designed specially for logic level (3V or 5V family) frequency
measurement.