Tektronix TCP300A, User Manual, Page: 42 / 82

Reference Notes
Measuring Differential Current
You can place two conductors in a current probe to provide differential or null
current measurement. (See Figure 11.) This avoids the necessity of using two
current measurement systems with a differential oscilloscope.
Figure 11: Measuring two conductors
WARNING. To avoid injury or loss of life from shock or fi re, do not put more than
one uninsulated conductor at a time in the probes.
An insulated conductor is de fi ned as any conductor that is surrounded by an
insulating material that is capable of isolating the voltage present on the conductor.
Note that lacquer coatings like those typically found on transformer windings do
not provide suf
fi cient, reliable insulation for use with current probes. The lacquer
coating can be easily nicked or damaged, compromising the insulating capabilities
of the lacquer coating.
Do not force the slide closed. Damage to the probe may result. If you cannot close
the slide around the conductor(s), either reduce the number of conductors you are
measuring, or, if possible, take your measurement on a smaller conductor.
1. Orient the two conductors under test so that the polarities oppose each other.
2. Clamp the current probe around the two conductors as shown. Be careful not
to pinch a conductor in the probe jaws.
24 TCPA300/400 Ampli fi ers and TCP300A/400 Series Current Probes User Manual