Gentec-EO UM-B - Manual (Page 11)

11
Revision 2.1
UM-B Series Instruction Manual Gentec Electro-Optics Inc. All rights reserved
3.3 When using an oscilloscope:
Figure 2.3: UM-B with oscilloscope
3.3.1 General Instructions
1- Install the wattmeter on its optical stand
2- Connect the wattmeter to the APM and switch it on. (Battery or power supply needed)
3- Connect the APM to the oscilloscope.
NOTE: The required load impedance is 1 M

and ≤ 30 pF.
4- Put the optical chopper (SDC-500 or equivalent) into the laser beam path and adjust the
frequency at 10Hz (laser beam must be contained within the aperture).
5- Put the wattmeter head into the laser beam path after the chopper (laser beam must be
contained within the aperture).
CAUTION: Be careful not to exceed the maximum levels and densities in: energy, peak
power and average power as stated in the specifications pages.
NOTE: As with all pyroelectric devices, these detectors have some position and beam size
sensitivity. For the most accurate measurements, the beam should normally be
centered on the sensor surface and the beam diameter should ideally be close to
that of the original calibration conditions, which is 100% encircled power (of a semi-