Figure
2
-
2.
Waveform Converslon
L
INPUT
WAVEFORM
SlNE
PK
PK
-
PK
RECTIFIED
SlNE
(FULL WAVE)
0
-?-
RECTIFIED
SlNE
(HALF WAVE)
1
SQUARE
PK
-
PK
RECTIFIED
SQUARE
PK
-
PK
0
RECTANGULAR
PULSE
D=X/Y
TRIANGLE
PK
-
PK
4
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
DISPLAY
PK
-
PK
2.828
1.414
2.828
1
.800
1 .800
0.9lD
3.600
Turn test circult power off and
discharge
all
capacitors before attemptlng In
-
clrcult reslst-
ance measurements.
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
dc. All ranges present an input impedance of 10 Ma. 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.
MEASUREMENT
0-PK
1.414
1.414
2.828
0.900
1
.800
0.9tD
1 .a00
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
%
=
100
x
Rs + (Rsf 107)
Where: Rs
=
Source resistance in ohms of
circuit being measured.
2.
AC VOLTAGE MEASUREMENTS
First, determine input impedance,
as
follows:
107
Zin
=
dl
+(2nF Rin C)
Where: Zin
=
effective input impedance
Rin
=
107
ohms
Cin
=
100
x
Farads
F
=
frequency in
Hz
Then, determine source loading error as follows:
Loading Error in
%
=
100
x
ZS
Rs
+
Zin
Where: Zs
=
source impedance
Zin
=
input impedance (calculated)
Rs
=
source resistance
MULTIPLIER
CONVERSION
RMS
1
.OOO
1
.ooo
1.414
0.900
1.272
0.9~'h
1.038
Figure
2
-
3.
Voltage Measurement Error Calculations
(Loadlng Error)
FOR
AVG
0.900
0.900
0.900
0.900
0.900
0.9D
0.900
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
identtjied by a "5Ol" preceding the serial
number. Units without the
"50/" are 60 Hz
models.
If
operation in both environments is
anticipated,
the50 Hz model is preferredsince
it provides
-60 dB rejection at both
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
To Next Page
Loading...
