HT Instruments HT4010 Bedienungsanleitung Seite 27

The instrument can perform the herewith measurements:
•
DC and AC Voltage up to 600V
•
Detection of AC Voltage without contact
•
AC Current up to 600A
•
Resistance and Continuity test
•
Diode test
Each parameter can be selected by rotating the 8-positions switch
included OFF position. To enable the hold function the HOLD key is
available. There are also
backlight, the RANGE key for manual selection of measurement
ranges, the MAX key for maximum value measurement of some
parameters and the MODE key for the selection of different features
common at the same position of selector rotation. The selected
quantity appears on a high-contrast liquid crystal display with
indication of measurement units and functions. The instrument
disposes of an Auto Power Off function consisting in an automatic
switching off 15 minutes after last selector rotation
2.1. TRMS/MEAN VALUE MEASURING INSTRUMENTS
Safety testers for alternate parameters are divided into two big
families:
•
MEAN VALUE instruments: instruments which measure only the
value of the wave at the fundamental frequency (50 or 60 Hz)
•
TRUE ROOT MEAN SQUARE instruments, also defined as TRMS:
instruments which measure the true root mean square value of
the quantity under test.
•
In presence of a perfectly sinusoidal wave, both families provide
identical results. In presence of distorted waves, the readings are
different. Mean value instruments provide only the value of the
fundamental wave while True RMS instruments provide the value
of the entire wave, including harmonics (within the passband of
the instrument). Accordingly, if the same quantity is measured
with both kinds of instruments, the measured values are identical
only if the wave is purely sinusoidal. Should it be distorted, True
RMS instruments provide higher values than medium value
instruments
2.2. TRMS VALUE AND CREST FACTOR DEFINITIONS
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key to activate/deactivate the display
HT4010