Tektronix TCP300A, Руководство пользователя

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Reference Notes
Measuring Noncontinuous Current with the TCP404XL Probe
When you measure a noncontinuous current with the TCP404XL probe, you
need to take into consideration several factors to ensure that you make accurate
measurements and do not trip the thermal overload circuit. The amplitude
and duty cycle of the continuous and noncontinuous current, and the ambient
temperature, all affect the maximum amount of time allowed for the measurement,
which de
fi nes the safe operating area of the probe.
You can calculate the duty cycle of the continuous and noncontinuous
current when you know the duration of the noncontinuous current (de
fi ned as
measurement time) and the measurement period. A continuous and noncontinuous
current is shown and how to calculate the duty cycle. (See Figure 15.)
Figure 15: Duty cycle calculation
After you calculate the duty cycle of the noncontinuous current you are measuring,
you can use the other factors (continuous and noncontinuous current amplitude,
etc.) to compare your measurement to those shown. (See Figure 35 on page 58.)
(See Figure 37 on page 59.)
You can see how duty cycle affects the measurement time by looking at any of
the three graphs. (See Figure 35 on page 58.) (See Figure 37 on page 59.) As the
duty cycle increases on the x-axis, the measurement time (of the noncontinuous
current) on the y-axis decreases.
30 TCPA300/400 Ampli fi ers and TCP300A/400 Series Current Probes User Manual