Resistance; Voltage Ac/ Dc; Current Ac/ Dc - Fluke 8020A Instruction Manual

DISPLAY
INPUT
MEASUREMENT
WAVEFORM
PK-PK
SlNE
2.828
PK
PK-PK
RECTIFIED
1.414
SlNE
(FULL WAVE)
0
RECTIFIED
2.828
SlNE
(HALF WAVE)
SQUARE
1 .800
PK-PK
RECTIFIED
1 .800
SQUARE
PK-PK
0
RECTANGULAR
PULSE
TRIANGLE
3 . 6 0 0
PK-PK
Figure 2-2. Waveform Converslon
NOTE
Any change (greater than one or two digits)in
apparent resistance when test leads are
reversed may indicate either the presence of a
diode junction or a voltage in the circuit.
CAUTION
Turn test circult power off and discharge all
2-27. Voltage ACIDC
2-28.
The 8020A is equipped with five ac and five dc
voltage ranges; 200 mV, 2V, 20V, 200V, 750V ac/ lOOOV
MULTIPLIER
FOR
CONVERSION
AVG
RMS
1.414
1 .OOO
0.900
1.414
1
0.900
2.828
1.414
0.900
0.900
0.900
0.900
1 .800
1.272
0.900
1 .a00
1.038
0.900
dc. All ranges present an input impedance of 10 M a . On
the ac ranges this is shunted by less than 100 pF. When
making measurements, be careful not to exceed the
overload limits given earlier in Table 2-1.
2-29. Measurement errors, due to circuit loading, can
result when making either ac or dc voltage measure-
ments on circuits with high source resistance. However,
in most cases the error is negligible (<0.1%) as long as
the source resistance of the measurement circuit is 10 kfl
or less. If circuit loading does present a problem, the
percentage of error can be calculated using the
appropriate formula in Figure 2-3.
1. DC VOLTAGE MEASUREMENTS
Loading Error in %
Where: Rs Source resistance in ohms of
=
circuit being measured.
2. AC VOLTAGE MEASUREMENTS
First, determine input impedance,
Zin
=
Where: Zin effective input impedance
=
Rin
= 1 0 7
Cin 100
=
F frequency in Hz
=
Loading Error in %
Where: Zs source impedance
=
Zin input impedance (calculated)
=
Rs source resistance
=
Figure Voltage Measurement Error Calculations
2-3.
(Loadlng Error)
NOTE
Noise rejection is optimized (-60 dB) when
the 8020A is operated in its normal line-
frequency environment, i.e., 50 or 60 Hz.
Units designed for 50 Hz environments are
number. Units without the "50/" are 60 Hz
models. If operation in both environments is
anticipated, the50 Hz model is preferredsince
it provides -60
frequencies on all voltage and current ranges.
2-30. Current ACIDC
2-3 1.
Four ac and four dc current ranges are included
on the 8020A; 2 mA, 20 mA, 200 mA and 2000 mA.
Each range is diode protected to 2 amps and fuse
100 x Rs
=
follows:
as
Rin
ohms
Farads
x
100 x
=
+
Zin
dB rejection at both
.