Output Enable; Photodiode Connections; Typical Connections - Keithley 2500 User Manual

2-4 Connections

Output enable

An interlock switch can be used with the Model 2500 output enable line on the Digital I/O
Port to inhibit the voltage bias source outputs. When output enable is activated, the
Model 2500 outputs will turn off when the lid of the test fixture is opened. However, you
must ALWAYS assume that power is present until you verify that the Model 2500 output is
off.
WARNING
See Section 12

Photodiode connections

Typical connections

Figure 2-3
diodes in a laser diode test setup.
NOTE
The two channels are being used as follows:
• Channel 1 biases and measures the current for the back detector photodiode. The cen-
ter conductor of INPUT CHANNEL 1 HI is connected to photodiode terminal while
the VOLTAGE SOURCE CHANNEL 1 terminal is connected to the other photodiode
terminal.
• Channel 2 is used to bias and measure the forward detector photodiode. The center
conductor of INPUT CHANNEL 2 HI is connected to one photodiode terminal while
the VOLTAGE SOURCE CHANNEL 2 terminal is connected to the other photodiode
terminal.
See Section
Model 2500 operating modes including making power measurements.
NOTE
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
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To prevent electric shock, test connections must be configured such
that the user cannot come in contact with conductors or any DUT that
is in contact with the conductors. Safe installation requires proper
shields, barriers, and grounding to prevent contact with conductors.
Operator protection and safety are the responsibility of the person
installing the product.
for complete details on using the output enable circuit.
shows typical connections to the back detector and forward detector photo-
The DUT can be biased and measured using only a triax cable with the ground
connect mode. See "Ground connect mode connections," page
4, "Photodiode Measurements,"
If an optional noise shield is used, connect the shield to INPUT LO (inner shield
of triax cable).
Model 2500 and 2502 User's Manual
for additional information on setting up
2-7.