3.2 Connecting components
LDC340 / Page 18
Should this be necessary (e.g. with laser diodes with integrated monitor diode and
common ground) the connection of the ground lines should be done as near as
possible to the laser diode to avoid measurement errors in measuring the monitor
diode current.
The internal monitor diode input may be operated without or with bias voltage (0 ...
10 V). The bias voltage is switched on via a delay-switch on the front panel.
(Refer to chapter 3.2.1, “Pin assignment of the output jack“ on page 15)
(Refer to chapter 3.9.4, “Adjusting the bias voltage of the monitor diode“ on page 24)
3.2.3.2 Connecting an external monitor diode
If an external monitor diode is used it must be connected via coaxial cable to the
corresponding jack
, PD ext. (AG)
at the rear panel of the LDC340.
The external monitor diode input offers no bias voltage and must be connected with
grounded anode (AG), that means the anode connected to the outer shield of the
BNC jack..
Attention
Input voltage / current must not exceed 15V / 5mA!
3.2.4 Laser voltage measurement
The LDC340 constantly measures the laser voltage at the output jacks of the unit.
For a precise measurement connect pin 6 directly to the LD-cathode and pin 9
directly to the LD-anode to avoid measuring the voltage drop in the connection lines
(4 pole measurement).