Keithley 6514, Instruction Manual, Page: 85 / 334

Amps Measurements 4-13
Applications
The following applications require an external voltage source. The Keithley Model 230 volt-
age source is fully programmable and can source up to 100V at 100mA.
With the proper use of external triggering between Models 6514 and 230, the tests can be
automated. All of the applications require a bias time or delay, which can be provided by the
delay feature of Model 6514. When Model 6514 is triggered, a measurement will not be per-
formed until the delay period expires.
NOTE External triggering and delay are covered in Section 9.
Diode leakage current
Figure 4-6 shows how to measure the leakage current for a diode. By sourcing a positive volt-
age, the leakage current through the diode will be measured. Note that if you source a negative
voltage, you will forward bias the diode. Resistor R is used to limit current in the event that the
diode shorts out or it becomes forward biased. Select a value of R that will limit current to 20mA
or less.
A profile for leakage current can be developed by measuring current at various voltage levels.
For example, you can program Model 230 to source from 1 to 10V in 1V steps. With the proper
use of external triggering, Model 6514 will perform a current measurement on each voltage step.
To ensure that the voltage is settled before each current measurement, you can program Model
6514 for a delay. For example, if you program Model 6514 for a one second delay, each mea-
surement will be performed after the voltage step is allowed to settle for one second. The current
measurements can be stored in the buffer.
NOTE
Buffer operation is covered in Section 8.
230
V-Source
A
+
-
6514
Ammeter
HI
LO
HI
LO
R
Diode
Equivalent Circuit
Figure 4-6
Connections; diode
leakage current test