THORLABS PDAPC2, User Manual, Page: 9 / 18

Si Switchable Gain Detector, OEM Chapter 3: Setup
Rev B, June 15, 2021 Page 7
Connect the remaining end to a measurement device such as an
oscilloscope or high-speed DAQ card.
Caution
Many high speed oscilloscopes have input impedances of 50 Ω .
In this case, do not install a 50 Ω terminator. The combined
loads will equal 25 Ω which could allow ~135 mA of output
current. This will damage the output driver of the PDA.
6. Power the PDAPC2 on. When the unit is on, the power indicator LED will
be illuminated yellow. If the LED is green or red, this indicates only one
power rail, either positive or negative, respectively, is connected. In that
case, the user would need to check the power inputs to make sure both
power rails are on and connected correctly.
7. Apply a light source to the detector, then adjust the gain controls to the
desired setting.
8. During alignment, the user should take appropriate precautions. For
example, ensuring the incident power is within safe operating power.
Additionally, the user should have proper eye and skin protection as
recommended by the light source manufacturer.