Keysight u2722a - Figure 2-8 Source Current Operation

2 Operation and Features
42 Keysight U2722A/U2723A User’s Guide
Figure 2-8 Source current operation
In Figure 2-8 (A), the U2722A/U2723A is having a source current of 20 mA to a
500 Ω load and it is measuring 10 V. As long as the DUT load line intersects the
source current line, it will be in source current mode and the current will maintain
at 20 mA. However in Figure 2-8 (B), it shows that when the resistance of the DUT
increases to 1 kΩ, the DUT load line intersects the input protection voltage line.
This forces the U2722A/U2723A to go into source voltage mode. Since the
voltage setting is clamped at 15 V and the U2722A/U2723A cannot operate out of
the boundary, the current then changes to 15 mA instead.
= 20 mA × 500 Ω
Input Protection Voltage line
15 V
10 V
V
meter
I
source
20 mA
Load line with R = 500
Ω
Source Current
line
15 V
V
meter
I
source
15 mA
20 mA
Input Protection Voltage line
R = 1 k
Ω
Load line with
Source Current line
V
meter
= I
source
× R
= 10 V
(A) Normal source current mode operation
I
source
= V
meter
/ R
= 15 V / 1 kΩ
= 15 mA
(B) Crossover to source current mode operation