This is a forwarded email reply from Chris Chapman.

----- Original Message ----- 
From: Meredith Lamb 
To: psn-l@..............
Sent: 3/8/2004 11:46:06 AM 
Subject: Re: new Wood-Anderson in Trieste

Hi all,
If anyone has the technical expertise to reply.... I'am wondering what is the
advantage (or disadvantage/s) of this item over that of acouple of single 
photogenerative cells?
It looks (more or less) like a half bridge circuit to me.
Take care, Meredith


----- Original Message ----- 
From: John or Jan Lahr 
To: psn-l@..............
Sent: 3/5/2004 9:03:08 PM 
Subject: Re: new Wood-Anderson in Trieste
I checked on the price of the 1L20.  It's $335
from On-Trak Photonics, Inc, Lake Forest, CA.
This is not an inexpensive solution, at least at this time!
John


To: psn-l@..............
From: John or Jan Lahr 
Subject: Fwd: new Wood-Anderson in Trieste
The clever, position-sensing system described by Dario Slejko (see below) may be of some interest to amateurs as well.  Note that the URL for Sitek given on his
web site should be:
http://www.sitek.se/
Cheers,
John
Hi Meredith,

       Looking at the 1L20 data sheet, the resolution is quoted as being about 100 nm. I am uncertain whether this refers to the use of the cell with a laser or not, but I suspect not. The semiconductor lasers may have 10x the noise of a tungsten filament bulb. You can get relatively quiet LEDs, but their construction does not often allow you to use them as point light sources and the change in light output over 0 to 100 deg C range may be a factor of x5. You do have quite a serious thermal stability problem, but it can be solved.
       It is relatively easy using large area Si photodiodes and a tungsten filament bulb to get a resolution of 15 nm at 10 Hz bandwidth. You can buy twin / quad photocells on a common substrate.

       Regards,




This is a forwarded email reply from Chris Chapman.
 
----- Original Message ----- 
From: Meredith Lamb 
To: psn-l@..............
Sent: 3/8/2004 11:46:06 AM 
Subject: Re: new Wood-Anderson in Trieste

Hi all,
If anyone has the technical expertise to reply.... I'am wondering what is the
advantage (or disadvantage/s) of this item over that of acouple of single 
photogenerative cells?
It looks (more or less) like a half bridge circuit to me.
Take care, Meredith




----- Original Message ----- 
From: John or Jan Lahr 
To: psn-l@..............
Sent: 3/5/2004 9:03:08 PM 
Subject: Re: new Wood-Anderson in Trieste
I checked on the price of the 1L20.  It's $335
from On-Trak Photonics, Inc, Lake Forest, CA.
This is not an inexpensive solution, at least at this time!
John


To: psn-l@..............
From: John or Jan Lahr <johnjan@........>
Subject: Fwd: new Wood-Anderson in Trieste
The clever, position-sensing system described by Dario Slejko (see below) may be of some interest to amateurs as well.  Note that the URL for Sitek given on his
web site should be:
http://www.sitek.se/
Cheers,
JohnHi Meredith,

       Looking at the 1L20 data sheet, the resolution is quoted as being about 100 nm. I am uncertain whether this refers to the use of the cell with a laser or not, but I suspect not. The semiconductor lasers may have 10x the noise of a tungsten filament bulb. You can get relatively quiet L