Hameg Instruments LCR-Bridge HM8118 Handbuch Seite 48

C o n n e c t i n g o f c o m p o n e n t s a n d m e a s u r e a c c e s s o r i e s
7 Connecting of components and
measurement accessories
For measuring components, it is necessary to use an adequate
measurement adapter. The measuring adapter is connected
with the 4 BNC jacks on the front panel of the LCR bridge
HM8118. For measuring leaded components we suggest a
HZ181, for SMD components the HZ188 should be used (con-
tained in shipment). High accuracy measurements should be
performed with a measurement adapter for 4 wire measure-
ments. A 2 wire measurement is not as accurate as a 4 wire
measurement adapter is. By using an adequate measuring
adapter parasitic impedances are minimized. For the highest
measurement accuracy it is advisable to perform an OPEN/
SHORT/LOAD calibration when-ever the test setup changes.
The latter is also advisable if the frequency is changed.
Alternatively, it is possible to use measurement leads instead of
a measurement adapter. The component may be connected to
the LCR bridge HM8118 via an appropriate measurement lead.
The measurement lead is connected to the bridge via the 4 BNC
jacks on the front panel. For high accuracy measurements we
recommend to use the Kelvin measurement lead (contained
in shipment), which is appropriate for 4 wire measurements.
Remark!
During a running measurement, do not touch the
component or bring it in contact with other objects.
Otherwise the measurement will be tampered.
Remark!
All components have to be discharged before
connecting! Do not apply external voltages to the
measurement inputs (front panel BNC jacks).
Remark!
Measurement accessories such as testing adap-
ters for measuring components have to be pulled
straight to disconnect.
7.1 4 wire measuring adapter HZ181
(with short circuit plate)
The 4 wire measuring adapter HZ181 (with short circuit plate) is
used to qualify leaded components. The measurement adapter
diverts the 4 wire measurement into a 2 wire measurement.
Fig. 7.1: 4 wire measurement adapter HZ181
The measuring adapter is connected directly with the 4 front-
panel BNC jacks. To measure the component, its pigtail ends
have to be inserted into the slots of the measurement contacts.
This accessory is not contained in shipment. The following
illustration shows the connection of the measurement adapter.
48
Subject to change without notice
Fig. 7.2: Connecting a measurement adapter
7.1.1 Specifications
Function:
Measurable components:
Frequency range:
Maximum voltage:
Connectors:
Safety standards:
Environmental conditions:
Operating temperature:
Storage temperature:
Weight:
7.1.2 Calibration
The measurement adapter HZ181, due to its construction,
has a stray capacitance, a residual inductance and a residual
resistance which impair the accuracy of the measurement
results. In order to minimize these influences it is necessary
to compensate for impedance measurement errors caused by
the adapter and the leads.
To compensate for these measurement errors an OPEN and
a SHORT calibration should be performed at the LCR bridge
HM8118. The procedure was described in chapter 6 „Calibra-
tion". For the SHORT calibration the measurement adapter
HZ181 comes with a shorting plate. Prior to the measurement
this shorting plate has to be inserted into the slots of the mea-
surement contacts. The calibration values obtained during the
calibration procedure will be stored in the LCR bridge HM8118
and remain valid until the next calibration.
If testing frequency dependent components, it is im-
portant to perform an OPEN and a SHORT calibration
for each of the 69 test frequencies.
Measurement adapter for
use with the LCR bridge
HM8118 (with 4 wire con-
nection)
Resistors, coils, capacitors
with axial or radial leads.
20Hz...200kHz
± 40V maximum (AC+DC)
BNC plugs (4), measurement
contacts (2)
EN61010-1; IEC61010-1;
EN61010-031; IEC61010-031;
Degree of pollution 2, inten-
ded to use indoors
+5 °C ... +40 °C
–20 °C ... +70 °C
about 200g