Table of Contents
Advertisement
Section
3
-Special Measurements
3.1 GENERAL.
The inclusion of the EXT DQ, BIAS, and OPP
ARM
jacks in the 1650-B permits many special meas-
urements to be made.
The EXT DQ jack allows ex-
tension of the DQ coverage at frequencies below 100
Hz, the
BIAS
jack allows a bias voltage or current to
be applied across or through an unknown impedance,
and the OPP
ARM
jack allows more accurate balancing
of reactive resistors.
The following section presents
a few of the many applications possible with these
external connection jacks.
3.2 APPLICATION O F D C BIAS T O CAPACITORS.
3.2.1 INTERNAL OSCILLATOR OPERATION.
Up to 600 V of dc bias may be applied to the un-
known capacitor by any of several different methods.
r )
DET
p
DET
The simplest method can be used for measuring only
series capacitance; fortunately, this is how most ca-
pacitors are specified.
WARNING
Charged capacitors form a shock hazard,
and care should be taken
to
ensure per-
sonal safety during measurement and to
be sure that the capacitors
are
dis-
charged after measurement.
The exter-
nal dc
supply
should also be handled
carefully.
It is advisable to limit the power that may be
drawn from the external dc supply t o 0.5 W (by a resis-
tor, fuse, or circuit breaker) in order t o protect the
bridge components in c a s e the unknown is short-cir-
cuited.
D D E T
Figure 3 -
1.
Methods of applying dc voltages to copacitance.
S P E C I A L M E A S U R E M E N T S
3-1
Advertisement
Table of Contents
