Tektronix TCP300A, User Manual, Page: 45 / 82

Reference Notes
Maximum Current Limits
Current probes have three maximum current ratings: continuous, pulsed, and
Ampere-second product. Exceeding any of these ratings can saturate the probe
core, magnetizing the core and causing measurement errors.
Maximum Continuous Current refers to the maximum current that can be
continuously measured at DC or at a speci
fi ed AC frequency. (See page 49,
Speci fi cations .) The maximum continuous current value is derated with
frequency; as the frequency increases, the maximum continuous current
rating decreases.
Maximum Pulsed Current refers to the maximum peak value of pulsed current
the probe can accurately measure, regardless of how short (within bandwidth
limitations) the pulse duration is.
Ampere-Second Product de fi nes the maximum width of pulsed current
that you can measure when the pulse amplitude is between the maximum
continuous and maximum pulsed current speci
fi cations. The maximum
continuous speci fi cation itself varies by frequency.
NOTE.
Always degauss the probe after measuring a current that exceeds the
maximum continuous current, maximum pulsed current, or Ampere-second
product rating of the probe. Exceeding these ratings can magnetize the probe
and cause measurement errors.
To determine if your measurement exceeds the Ampere-second product, perform
either Procedure A (Maximum Allowable Pulse Width), or Procedure B
(Maximum Allowable Pulse Amplitude).
TCPA300/400 Ampli fi ers and TCP300A/400 Series Current Probes User Manual 27