![background image](http://html1.mh-extra.com/html/keithley/2651a/2651a_reference-manual_661729205.webp)
Section 4: Theory of operation
Model 2651A High Power System SourceMeter® Instrument Reference Manual
4-8
2651A-901-01 Rev. A / March 2011
Figure 72: Model 2651A I-source load considerations
V-meter
(V
M
)
5 V
10 V
100 mA
A: Normal I-source operation
Programmed source value:
100
mA
Actual source value:
100
mA
V
V
10
10
10
0
0
0
mA
I-source
(I
S
)
Voltage
compliance
limit line
Voltage
compliance
limit line
Voltage
compliance
limit line
Power
compliance
limit line
Programmed current
source value line
Programmed current
source value line
Operating
point
50
Ω
DUT
Loa
d L
ine (R
)
V-meter
(V
M
)
5 V
10 V
100 mA
50 mA
B: I-source operation in voltage compliance
Programmed source value:
100
mA
Actual source value:
50
mA
C: I-source operation in power compliance
Programmed source value:
100
mA
Actual source value:
30
mA
I-source
(I
S
)
Operating
point
2
0
0
Ω
DU
T
Lo
a
d
L
in
e
(R)
V
M
=
I
S
• R
= (100 mA) (50
Ω
)
=
5 V
I
S
=
V
M
/ R
= 10 V / 200
Ω
=
50 mA
Programmed current
source value line
V-meter
(V
M
)
5 V
10 V
100 mA
50 mA
I-source
(I
S
)
Power limited
voltage compliance
limit line
Operating
point
I
S
=
V
M
/ R
= 6 V / 200
Ω
=
30 mA
t
Power
compliance
limit line
U
T
oa
n
R)
2
0
0
Ω
DU
T
Lo
a
d
L
in
e
(R)
X