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Entry  Sat Feb 12 08:08:05 2011, Suresh, Update, Electronics, REFL11 Photodiode replaced C30642_datasheet-1.pdf40mUpgradeREFL11schematic.pdfP2120572.JPGP2120565.JPGP2120571.JPG
    Reply  Sat Feb 12 23:22:21 2011, rana, Update, Electronics, REFL11 Photodiode replaced 
       Reply  Sun Feb 13 16:20:53 2011, Suresh, Update, Electronics, REFL11 Photodiode replaced 
    Reply  Sun Feb 13 02:33:37 2011, Koji, Update, Electronics, REFL11 Photodiode replaced 
Message ID: 4275     Entry time: Sat Feb 12 08:08:05 2011     Reply to this: 4276   4277
Author: Suresh 
Type: Update 
Category: Electronics 
Subject: REFL11 Photodiode replaced 

A new photodiode ( Perkin and Elmer Model no. C30642GH Sl No.1526) has been installed in the place of the old photodiode.  The datasheet of this model is attached. 

The 68pF capacitor which was present in parallel with the photodiode has been removed.  Here is a picture of the PCB ( in all its gory detail!) and the photodiode after replacement.

  P2120565.JPG   P2120571.JPG

 

I also checked to see if we have a DC output from the new PD.  With 375mW of 1064nm light incident we have 15mV of output.  Which matches well with the typical Reponsivity of 0.8V/A reported in the datasheet and our REFL11 ckt .  The schematic of the ckt is also attached here for easy reference.  The various factors are

V_dc = 0.375 mW x 0.8 V/A x 10 Ohm x 5 = 15mV

The last factor is the gain of the last stage on the DC route.

When I reassembled the box I noticed that there is problem with the SMA connectors popping out of the box.  The holes seem misplaced so I enlarged the holes to remove this concern.

P2120572.JPG

 

Attachment 1: C30642_datasheet-1.pdf  150 kB  | Hide | Hide all
C30642_datasheet-1.pdf C30642_datasheet-1.pdf C30642_datasheet-1.pdf C30642_datasheet-1.pdf C30642_datasheet-1.pdf
Attachment 2: 40mUpgradeREFL11schematic.pdf  152 kB  | Hide | Hide all
40mUpgradeREFL11schematic.pdf
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