Application Reference
Application
Reference
The high-frequency AC / DC current probe can be used in many measurement fields,
such as new energy vehicle design, switching power supply design, electrical
engineering, semiconductor device design, avionics design, inverter/transformer
design, electronic ballast design, Industrial control/consumer electronics design,
engine drive digital design, power electronics and power transmission practical
design, etc. Below we introduce several common measurement applications:
Inductance Measurement
Use a current probe to measure the coil inductance of a low- or high-impedance pulse
source of known value:
Low impedance pulse source
Connect the sensor to the output of the pulse generator.
Keep the voltage on the inductor constant.
Clip the current probe to one of the current source leads.
Measure the current sawtooth wave. The inductance is effectively defined by the
slope
1.
2.
3.
4.
of the current sawtooth wave shown here.
Calculate the inductance using the following
formula:
The L is the inductance in Henries. E is the voltage of the pulse generator, dt is the
time change, and di is the current change.
Note: If the probe impedance is a significant part of the overall circuit inductance, the
measurement accuracy will be affected. For information on probe insertion
impedance, see Probe Specifications.
The figure below shows a constant voltage pulse generator with very low output
impedance connected to a low resistance inductor.
7
