03 | Keysight | Using an External Trigger to Measure Current with B2980A Series – Demo Guide
Concept
Figure 1 illustrates the connection diagram and basic setup conditions for the demo,
which uses a B2985A/87A ammeter to make current measurements whenever it receives
an external trigger signal. The B2980A series will measure current using the settings
shown below while sourcing voltage across the resistor.
Figure 1. Connection diagram and basic condition
Figure 2 shows the parameters used to define the measurement timing from the instru-
ment’s front panel. The specified source value is outputted immediately after pressing
Voltage Source . Next, you will need to configure the B2985A/87A ammeter to
accept an external trigger and make a current measurement.
Figure 3 shows the external trigger signal requirements to initiate a current measurement
from the ammeter. Positive or negative logic can be used to set the external trigger pulse.
A
Input
Common
High
Low
B2985A/87A
Ammeter
B2985A/87A
Voltage Source
External Trigger Signal
Trigger In
DUT
: 100 GΩ Resistor
Sourced Voltage
: 1 V
Measure Delay
: 300 μs
Trigger Count
: Any or INF.
J1
J2
N1422A (DUT)
-
Figure 2. Timing chart for the current measurement
External Trigger
Output ON
Source Value
Output
Off State
V
Time
T
MD
T
AP
T
MD
T
AP
T
MP
T
MD
T
AP
T
MP
T
MP
T
AP
: Aperture Time
T
MD
: Measure Delay
T
MP
: Measure Trigger Period
: Measurement
t
W
: Trigger Pulse Width > 10 µs
t
W
V
Time
Positive Logic
5 V
V
Time
Negative Logic
5 V
t
W
Figure 3. External trigger signal requirements
