Constant Voltage Source; Constant Current Source; Other Conditions - IET Labs, Inc. RLC Digibridge 1693 User And Service Manual

1693 RLC Digibridge

3.4.3 Constant Voltage Source

If it is important to measure the DUT at a particular
test voltage, then select the constant-voltage feature
as follows. Press:
[SHIFT] [CONSTANT VOLTAGE]
so that the CONSTANT VOLTAGE indicator is lit.
The Digibridge now retains a source resistance of 25
ohms for all ranges. The voltage is constant for any
DUT impedance significantly larger than 25 ohms.
An example is given in the preceding paragraph.
Choosing this feature causes a reduction in measure-
ment accuracy by a factor of three, as accounted for
by Kcv in the accuracy specifications. (To disable the
constant-voltage feature, press the same keys again.).

3.4.4 Constant Current Source

If it is important to measure the DUT with a particular
test current applied, then select the constant current
feature as follows.
1. Select ENTER with the [FUNCTION] key.
2. Enter the desired current in milliamps.
For example, to enter .2 mA press [.][2][=][SHIFT)
[CONST I].
To disable Const. I, press: [0][=][SHIFT][CONST
I]. Refer to Table 3-8 for a listing of constant-current
source values.
CURRENT
51 nA –
RANGE 13.1 µA
SOURCE
97.4 k
RESISTANCE
RANGE
1
Table 3-8: Current Range and Source
Resistance
44
13.2 µA - 200 µA- 3.2 mA -
198 µA 3.195 mA 51 mA
5.6 k 400 ohms 25 ohms
2 3 4
When Const. I is enabled, the following procedure
can be used to determine the current, voltage, and
range set.
1. Select ENTER with the [FUNCTION] key.
2. For current, press: [SHIFT)[CONST I], cur-
rent will be displayed in mA.
3. For voltage, press: [SHIFT][VOLTAGE],
voltage will be displayed in V.
4. For range, press: [SHIFT][SPECIAL][l], the
range will be displayed.
To calculate the actual current through the DUT, use:
I = V/(Rs + Zdut).

3.4.5 Other Conditions

Other test conditions are described in other parts of
this manual.
Delay (programmable settling time before acquisition
of data) - paragraph 3.5.3.
Averaging (selection of number of measurements to
be averaged) - paragraph 3.6.3
Bias applied to the DUT (if it is a capacitor) - refer
to paragraph 3.7
Special functions - refer to paragraph 3.10.
Operation