5
drain ghost voltages leaving mainly hard signal values on meter readings. It is an
invaluable feature for precise indication of hard signals, such as distinguishing between
hot and open wires (to ground) in electrical installation applications.
2)
AutoV Mode
input impedance increases abruptly from initial 2.1
kΩ to a few
hundred kΩ’s on high voltage hard signals. “
LoZ
” displays on the LCD to re
mind the
users of being in such a low impedance mode. Peak initial load current, while probing
1000VAC for example, can be up to 673mA (1000V x 1.414 / 2.1
kΩ)
, decreasing
abruptly to approx. 2.1mA (1000V x 1.414 / 670
kΩ) within a fraction of a second.
Do
not use AutoV mode on circuits that could be damaged by such low input impedance.
Instead, use rotary selector or high input impedance voltage modes to minimize
the test loadings for such circuits.
ACV; VFD-ACV; dBm (Model 789 only)
Inputs are made via the test lead terminals
V-COM
. Press the
SELECT
button
momentarily to select the
subject functions in sequence. Last selection will be saved as
power up default for repeat measurement convenience.
Note:
In
dBm
function, power up default reference impedance will be displayed for 1
second before displaying the dBm readings. Press
dBm-
(
RANGE
) button
momentary to select different reference impedance of 4, 8, 16, 32, 50, 75, 93, 110,
125, 135, 150, 200, 250, 300, 500, 600, 800, 900, 1000, up to 1200
. Last selection
will be saved as power up default for repeat measurement convenience.
Summary of Contents for BM785
Page 1: ...USER S MANUAL BM789 BM786 BM785 Digital Multimeter ...
Page 22: ...21 ...
