Manual

Reference Notes
Extending Cur
rent Range
You may encounter situations where your measurement exceeds the maximum
current rating of the connected probe. This section discusses methods for
extending AC
and DC current ranges without exceeding specified limits.
WARNING. To avoid personal injury or loss of life due to shock or fire, do
not exceed the specified electrical limits of the TCPA300 and TCPA400 or any
applicable accessories. When using multiple conductors, do not exceed current
limits on either conductor.
Extending DC Range
If you wan
t to measure a low-amplitude AC component that is superimposed on
an extremely large steady-state DC component (such as in a power supply), or
if you want to extend the DC current range of your probe, you can add offset
(bucking) current with a second c onductor.
WARNING. To avoid injury or loss of life from shock or fire, do not put more than
one uninsulated conductor at a time in the probe jaws. An uninsulated conductor
is defi
ned as any conductor without insulation or w ithout insulation rated for the
voltage present on the conductor under test.
To su
pply additional bucking current, do the following and refer to the illustration.
(See Figure 15.)
1. Pla
ce a second conductor that has a pure DC component of known value in
the probe jaw with the conductor under test.
2. Or
ient the second conductor so that the bucking current flows in the opposite
direction of the DC flow in the conductor under test.
3
.
T
o determine measurement values, add the value of the bucking current to
the d isplayed measurement.
Figure 15: Adding a second conductor
30 TCPA300/400 Amplifiers and TCP300/400 Series Current Probes User Manual