Voltech AT360, User Manual

Page: 398 / 470

T
ESTS AND
T
EST
C
ONDITIONS
P
AGE
7-100 V
OLTECH
AT
I
U
SER
M
ANUAL
7.1.24 Z, ZB – I
MPEDANCE
, I
MPEDANCE WITH
B
IAS
Measurement
Range
Test
Voltage
Test
Frequency
Basic
Accuracy
1m
Ω
to 1M
Ω
1mV to 5V 20Hz to 3MHz 0.2%
The impedance of a transformer is usually complex, that is it consists of
real (resistive) and inductive or capacitive (imaginary) parts. The total
impedance at a specified frequency is the vector sum of these parts.

Z

=
√√√√
(R
2
+X
2
)
Where R and X are the real and imaginary parts of the total impedance.
The impedance test checks the impedance of audio and telecommunications
transformers that are to be used with transmission lines of specified
impedance. The test helps to ensure that the transformer has been assembled
properly using the correct core and winding materials.
Test Conditions
The test may be made on the part alone, or with a load resistor RL attached to
the secondary to simulate the load impedance of the transformer when it is
used in its final application. The optional load resistor (RL) is connected to the
transformer under test as shown. This may be done automatically using the
tester’s OUT test.