Filter
Top Products
Using WT3 to Measure a Resistor
Before starting, make sure the WT3 unit has been calibrated and has stabilized for at least 90 seconds.
Measure the value of a resistor as follows:
•
Launch the WT3 software and make sure the volume is set at maximum.
•
Make sure that the resistor is not connected to any other equipment and then connect the test
leads of the WT3 unit to the resistor under test.
•
Click the "Measure Free-Air Parameters" button at the left side of the WT3 screen.
•
The sweep is silent, then the impedance is plotted and the parameters are displayed.
•
Read the value of the resistor in the R(e) field at the right side of the screen. Ignore the other
parameter fields.
•
Repeat the measurement to confirm the result. Repeat measurements should be in good
agreement.
Here is a typical result when measuring a 10 Ohm resistor:
An ideal resistor would have a perfectly flat impedance response at exactly the rated value of the
resistor. Notice that the measured impedance (shown above in blue) of this 10 Ohm precision resistor
is almost perfectly flat over the audio frequency range. This is not unusual for a resistor because real
resistors typically do behave largely as ideal resistors. The impedance phase response is essentially flat