HP 4284A - Page 176

Figure 6-4. Inductance Circuit Mode Selection
The following is a rule of thumb for selecting the circuit mo de
according to the imp edance of the inductor.
 Below approx. 10  : use series circuit mo de
 Above approx. 10 k : use parallel circuit mo de
 Between ab ovevalues : follow the manufacturer's
recommendation
For example, to measure a 1 mH inductor at the 1 kHz (imp edance
may b e approximately 6.3 ), L
s
-D or L
s
-Q function is suitable.
Signal Level
Most comp onents have imp edance characteristics that are dependent
on the applied signal level. So, the oscillator level setting should b e
set appropriate for the DUT.
Signal Level
Across The DUT
Figure 6-5 shows a simplied mo del of the HP 4284A and a DUT.
The signal level across the DUT depends on the oscillator level, the
source resistance of the HP 4284A, and the imp edance of the DUT,
as follows.
j V
m
j =
j Z
x
j
j R
so
+Z
x
j
2j V
osc
j
j I
m
j =
j V
osc
j
j R
so
+Z
x
j
Where, j V
osc
j : oscillator voltage level of the HP 4284A,
R
so
: Source resister of the HP 4284A (= 100 ),
j V
m
j : Signal voltage level applied on DUT,
j I
m
j : Signal current level owed in DUT,
j Z
x
j : Imp edance of DUT.
Measurement Procedure and Examples 6-7