Manual

Reference Notes
Measuring Dif
ferential Current
You can pla ce two conductors in a current probe to provide differential or null
current measurement. (See Figure 10.) This avoids the necessity of using two
current meas
urement systems with a differential oscilloscope.
Figure 10: Measuring two conductors
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 TCP303 or TCP404XL probes. Do not
put any uninsulated conductors in the TCP305 or TCP312 probes. An uninsulated
conduc
tor is defined as any conductor without insulation or without insulation
rated for the voltage present on the conductor under test.
An ins
ulated conductor is defined as any conductor that is surrounded by a n
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 sufficient, 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
me
asuring, 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.
22 TCPA300/400 Amplifiers and TCP300/400 Series Current Probes User Manual