Boonton Electronics 71A, 71AR - Page 21

CORRECTION FOR ERROR IN CAPACITANCE MEASUREMENT OWING TO SERIES INDUCTANCE
OF RG-62/U CONNECTING CABLES HAVING COMBiNED LENGTH OF 1 FOOT
PI ~
to-'
(SEE IMPORTANT NOTES BELOW)
):I
1000 pF
V
7
,/
,/'
./
4
/
,/
W
U
2
./
Z
,/
<C(
t-
,/'
O
/
<C(
100pF
0..
<C(
-7
/
U
t-
V
V
VI
w
./'
4
t- v
2
./
/
v
y
w
/
I
10pF
1.0
2
4 7
2 4 1
2 4
7
2 4
7
2 4 7
0-0001 pF
O.OOlpF O-OlpF O·lpF
I p F
10pF
SUBTRACT pF FROM CAPACITANCE READING
FOR EACH FOOT OF RG-62/U CONNECTING CABLE
NOTES
1. Since the effect of series inductance is to cause an .apparent increase in capacitance,
the correction is subtracted from the measured value.
2. Correction values shown in this table are for a pair of RG-62/U cables having a
combined length of 1 foot. (correction for RG-58/U are not substantially different.)
The two cables need not be of the same length.
3. Since the correction is very nearly a direct function of cable length for small cor-
rections (10% or less), the correction for cable pairs of other lengths may be computed
from the ratio to 1 foot.
4. It is essential that BOTH ends of the cable shields be well grounded.
Figure 3-1