General Description - Ht 3013 Mode D'emploi

2. GENERAL DESCRIPTION

The instrument can perform the herewith measurements:
•
DC and AC TRMS Voltage up to 600V
•
Detection of AC Voltage without contact
•
DC and AC TRMS Current up to 400A
•
Resistance and Continuity test
•
Frequency with test leads
•
Diode test
•
Capacitance
•
Temperature with type K probe
Each parameter can be selected by rotating the 8-positions switch
included OFF position. There are also the H,
MODE for the use of which see § 4.2. 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
30 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
•
Only 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)
2.2. TRMS VALUE AND CREST FACTOR DEFINITIONS
The effective value of a g(t) alternate signal is defined by the below
expression:
The effective value is indicated as RMS (Root Mean Square). The
Crest Factor is defined as the ratio between the peak value of a
signal and its effective value:
This value varies according to the waveform of the signal. For a
purely sinusoidal wave it's worth
distortions the Crest Factor assumes higher values as long as the
wave distortion is higher
29
G =
RMS
G
p
CF (G)=
G
RMS
2
HT3013
, PEAK, REL and
=1.41. In presence of