User manual

Reference Notes
3-4
TCPA300/400 Amplifiers and TCP300/400 Series Current Probes Instruction Manual
1. Select the range setting that will display the maximum detail without
exceeding the dynamic range of the signal.
2. Adjust the oscilloscope V/div sensitivity (A/div if using the TEKPROBE
interface), to display maximum signal detail.
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. See Specifications
beginning on page 4--1 for the maximum current ratings of compatible probes.
H Maximum Continuous Current refers to the maximum current that can be
continuously measured at DC or at a specified AC frequency. The maximum
continuous current value is derated with frequency; as the frequency
increases, the maximum continuous current rating decreases.
H 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.
H Ampere-Second Product defines the maximum width of pulsed current that
you can measure when the pulse amplitude is between the maximum
continuous and maximum pulsed current specifications. The maximum
continuous specification 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 or Procedure B .
To determine the maximum allowable pulse width, measure the peak current of
the pulse (see Figure 3--3a). Divide the Ampere-second (or Ampere-microse-
cond) specification of your probe by the measured peak current of the pulse. The
quotient is the maximum allowable pulse width; the pulse width at the 50% point
of the measured signal must be less than this value.
For example, the TCP312 Current Probe has a maximum Ampere-second
product of 500 A⋅s in the 10 A/V range setting. If a pulse measured with a
TCP312 has a peak current of 40 A, the maximum allowable pulse width would
be 500 A⋅s divided by 40 A, or 12.5 s.
Procedure A