Amprobe AM-42 Multimeters - Manual (Page 4)

4
-DCV & ACV functions (AM-42 only)
Rotate the rotary selector to the V position selects common impedance (Hi-Z) voltage measurements. DCV is the
default function. The DC annunciator “
” turns on. Press SELECT button momentarily to select ACV. The AC
annunciator “ ” turns on.
-Resistance, Continuity, Diode & Capacitance functions (AM-42 only)
Rotate the rotary selector to the
Ω/ / / position. Resistance “ Ω”is the default function.
Press SELECT button momentarily selects Continuity function. The Audible annunciator “ ” turns on. Continuity
is convenient for checking wiring connections and operation of switches. A continuous beep tone indicates a
complete circuit.
Press SELECT button momentarily AGAIN selects Diode test function. The annunciator “
” turns on. The
reading shows the approximate voltage drop across the test leads. Normal forward voltage drop (forward biased)
for a good silicon diode is between 0.400V to 0.900V. A reading higher than that indicates a leaky diode
(defective). A zero reading indicates a shorted diode (defective). An OL indicates an open diode (defective).
Reverse the test leads connections (reverse biased) across the diode. The digital display shows OL if the diode is
good. Any other readings indicate the diode is resistive or shorted (defective).
Press SELECT button momentarily AGAIN selects Capacitance function.
-Frequency function (AM-42 only)
Rotate the rotary selector to the Hz position selects Frequency function.
*Unlike the Line Level Hz Frequency function (for AM-47 only) as stated, this (Common) Hz Frequency function is
set only at the highest input sensitivity mainly for measuring small electronic signals of below 20VAC rms.
4-3) OTHER FEATURES
-Power On & Off
For models AM-47 and AM-45, press and hold the SELECT button for 1 second and then release to turn the
power ON or OFF. Press and hold the SELECT button for approximately 6 seconds to master reset the system to
the default stage if in case the meter hangs up unexpectedly.
For model AM-42, rotate the rotary selector to turn the power ON or OFF.
-Auto Power Off
Models AM-47 and AM-45 turn off after approximately 3 minutes of idle measurement readings and no
button/switch activities. Model AM-42 turns off automatically after approximately 30 minutes of no button/switch
activities.
-HOLD and 30ms MAX features (AM-42 only)
The Hold feature freezes the display for later viewing. Press the HOLD (MAX ) button momentarily to activate
or to exit the Hold feature.
The Max feature captures voltage signals that have durations as short as 30ms (milliseconds) within a single
range, and has automatic up range capability. This mode is available in DCV & ACV functions. Press the HOLD
(MAX ) button for 1 second or more to activate or to exit the Max feature.
-Auto-ranging
If the function selected has more than one range, the meters will auto-range to the best range and resolution. No
manual ranging is required.
5) MAINTENANCE
WARNING
To avoid electrical shock, disconnect test leads from live circuits before opening the case. Do not operate with
open case.