Hioki RM3545, Instruction Manual, Page: 315 / 364

Appendix 3 DC and AC Measurement
A3
A
ppend
ix
Resistance (impedance) measurement can be performed using the DC or AC method.
•
DC method
RM3542, RM3543, RM3544, RM3545, RM3548 resistance meters
Standard digital multimeters
Standard insulation resistance meters
•
AC method
3561, BT3562, BT3563, 3554 Battery HiTesters
Standard LCR meters
The DC measurement method is used widely in applications such as measurement of gen-
eral-purpose resistors, winding resistance, contact resistance, and insulation resistance. In
the DC method, the measurement setup consists of a DC power supply and a DC voltme-
ter. While its simple circuitry makes it easier to increase accuracy, it is prone to measure-
ment errors due to electromotive force that may be present in the measurement path.
See: "Appendix 9 Effect of Thermal EMF" (p.A23)
The AC method is used when it is not possible to measure using DC, for example in imped-
ance measurement of inductors, capacitors, or batteries. Since an AC ohmmeter consists
of an AC power supply and an AC voltmeter, it is not affected by DC electromotive force.
On the other hand, caution is necessary since results differ from those obtained using DC
measurement, for example due to components such as core loss in coils’ series equivalent
resistance.
Appendix 3 DC and AC Measurement
DC ohmmeter AC ohmmeter
Measurement
signal
Detection volt-
age DC AC
Advantages High-precision measurement is possi-
ble. Not affected by electromotive force. Re-
actance measurement is possible.
Disadvan-
tages Affected by electromotive force since
not capable of performing DC superim-
posed measurement. (Thermal EMFs
can be corrected by the OVC function.) Difficult to increase precision.
Applications DC resistance of windings such as
transformers and motors, contact resis-
tance, insulation resistance, PCB wiring
resistance Battery impedance, inductors, capaci-
tors, electrochemical measurement
Measurement
range
10
-8
to 10
16
10
-3
to 10
8
Hioki
instruments Ohmmeters : RM3542 to RM3548
DMMs
: 3237 to 3238
Insulation resistance meters
: IR4000 series, DSM series
Battery HiTesters
: 3561, BT3562, BT3563
LCR meters
: 3570, IM3533, IM3523, etc.
DC power
supply
DC voltmeter
AC power
supply
AC voltmeter