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How to connect the components
and the accessories
In order to measure components a suitable test fi xture is ne-
cessary. Fixtures are connected to the instrument via the 4 front
panel BNC connectors. There are different fi xtures for through-
hole and SMD components. Precision measurements require
4 wire connections. The fi xtures provided minimize parasitic
elements. The three-step cal procedure must be repeated each
time the test set-up or the frequency is changed.
As an alternative to fi xtures test leads may be used, the compo-
nent to be measured can be connected by suitable test cables
to the 4 BNC front panel connectors of the HM8118. Also in
this case a 4 wire measurement will be more precise than a 2
wire measurement. Use Kelvin test cables made especially for
4 wire measurements.
Please note:
Do not touch the component under test with the
hands or other objects, this is especially important
in case of high impedance measurements, other-
wise the result will be in error.
STOP
Please note:
Discharge all components before connecting them!
Do not apply any voltages to the test terminals!
Please note:
STOP
Remove all test fi xtures by pulling straight towards
you.
STOP
Beispiel: Anschließen eines Testadapters
M e a s u r e m e n t s w i t h t h e P r o g r a m m a b l e L C R B r i d g e H M 8 1 1 8
Measurements with the
Programmable LCR Bridge HM8118
The following table lists all functions provided by the LCR
Bridge HM8118:
L-Q
Inductance L and quality factor Q
L-R
Inductance L and resistance R
C-D
Capacitance C and loss tangent D
C-R
Capacitance C and resistance R
R-Q
Resistance R and quality factor Q
Z- Θ
Apparent impedance (admittance) Z and phase angle Θ
Y- Θ
Apparent conductance Y and phase angle Θ
R-X
Ohmic resistance R and Reactance X
G-B
Conductance G and susceptance B
N- Θ
Transformer turns ratio N and phase angle Θ
M
Transformer mutual inductance M
Measuring frequency
The LCR Bridge HM8118 features a frequency range fo 20 Hz to
200 kHz in 62 steps with a basic accuracy of 0.05 %. Adjust the
frequency by pressing the button FRQ
6
or the arrow buttons
7
; during frequency adjustment the
FRQ and the arrow buttons will light up. A change of frequency
may cause a change of series to parallel circuit parameters
or vice versa if the AUTO function is activated and the impe-
dance rises beyond 1000 ohms. With high impedances and at
mains frequencies of 50 or 60 Hz instabilities may occur if the
measuring frequency is either 100 or 120 Hz because of beat
frequencies; it is hence advisable to stay away from harmonics
of the actual line frequency.
Measuring voltage
The LCR Bridge HM 8118 generates sinusoidal voltages from
20 mV
to 1.5 V
with a resolution of 10 mV
rms
rms
error is < 5 %. This voltage is applied to the component under
test, the source impedance will be automatically adapted to
the range as follows:
Component impedance
3 Ω
10 uΩ
to
3 Ω
to 100 Ω
100 Ω
to 1.6kΩ
1,6 kΩ
to 25 kΩ
25 kΩ
to
2 MΩ
2 MΩ to 100 MΩ
The output resistance depends to the selected range.
Constant voltage CST V
In some cases a measurement will require a test voltage not
available with the standard voltage in that range. In such cases
a constant voltage (CST V) may be selected using the menu
function SETUP which is called by pressing SELECT
the arrow buttons
7
and the KNOB
CST V to ON; this will set the source impedance to 25 Ω. For all
components with impedances > 25 Ω the voltage will remain
nearly constant. In order to prevent overloading the bridge the
selected range may automatically change, depending on the
impedance of the component. Constant voltage operation will
8
and using the KNOB
. The amplitude
rms
Source impedance
25 Ω
25 Ω
400 Ω
6,40 kΩ
100 kΩ
100 kΩ
3
. Use
6
to set the parameter
Subject to change without notice
37
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