Large-Area Balanced Photoreceivers Operation • 7
Using the Photoreceiver
1. Check the battery voltage. The Model 23X7 can
be powered by a single 9-volt alkaline battery or an
external power supply. If you are using a battery,
check the battery condition by pushing the red
power switch to the BATT CHK position. If the
green LED lights up, the battery is in good condi-
tion; if the LED does not light, the battery needs to
be replaced (see page 8).
2. Mount the photoreceiver. Use the 8-32 thread
(M4 for metric versions) on the bottom of the
casing to mount the photoreceiver to a post or
pedestal.
The threading is seated in a non-conductive plastic pad to
reduce the electrical noise associated with ground loops. Be
careful not to over-tighten when attaching the casing to a
post or pedestal, or the threaded insert can strip out of the
plastic pad.
3. Connect the receiver output. Connect your
voltmeter, oscilloscope, or other instrument to the
Output BNC connector on top of the receiver.
4. Turn the power switch to “on.” The output
voltage should register on your scope or other
instrument.
5. Align optical beams onto the detectors.
Be careful to keep the optical intensity for each
detector under the damage threshold (6 mW/mm2
for Model 2317, 10 mW/mm2for the Model 2307).
6. Adjust the gain. Use the black switch on top of
the receiver to set the gain to low, medium, or high.
The bandwidths vary with the gain setting (the
label on the front of the photoreceiver indicates
the gain and bandwidth values).
7. Balance the optical input levels. Alternately
block each diode and observe the signal strength.
When they are approximately equal and opposite,
23x7 LA Blncd Rcvr revA.fm Page 7 Tuesday, September 28, 2004 1:59 AM
