© Kurth Electronic GmbH, All Rights Reserved
16
Line voltage measurement
In all test modes (except
Continuity
) as well as in standard mode the
KE890/895 measures the applied voltage between the two measuring points.
The KE890/895 is high-impedance (~2 MΩ), so the line is not loaded. The
measurement is carried out via the banana plugs or on the wires 4 / 5 of the
RJ45 plug or on the pins 3 / 4 of the RJ11 plug.
Warning:
The banana plugs and the corresponding wires of the RJ45
or RJ11 plugs are directly connected to each other. Never connect
several connectors at the same time, as otherwise voltages will be
fed to other devices and could damage them!
The respective status is indicated by the LEDs
REV
/
OK
and
Cont
:
Green LED
OK
lights up:
Positive polarity
(plus at red plug, minus at black plug)
Red LED
REV
lights up:
Negative polarity
(plus at black plug, minus at red plug)
LEDs
REV
and
OK
light up alternately:
AC voltage
In analogue telephone lines, the A wire has a negative assignment (minus)
and the B wire has a positive assignment (plus).
The level of the respective voltage is indicated by the brightness of the LED
Cont
. From a voltage of approx. 2 – 3 Volt it glows weakly. From a voltage of
approx. 100 Volt it shines stronger. Thus the line voltage can be estimated
approximately. From ~95 Volt the red warning LED (
>100V
) also lights up and
a periodic alarm signal sounds.
If the line is busy and the supply voltage is 10 – 20 volts, the
Cont
LED lights
up darkly.
In general, the KE890/895 can be used to check every voltage source for
polarity, type of voltage (DC or AC voltage) and approximate voltage level in
a range up to 100 volts.
In
ETH Link
and
Continuity
modes, the line voltage is not displayed. In these
modes, the
Cont
LED is used to indicate the test being performed.
