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I ask a never seen electronic part.

Johnny Lee

Oct 31, 2016
3
Joined
Oct 31, 2016
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To Whom It May Concern,

I ask a never seen electronic part in laser pulser.

What is a part type or name in RED Circle ?

Thank you.

Best Regards,

asksomething.png
 

hevans1944

Hop - AC8NS
Jun 21, 2012
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Could be a 4.7 ohm power resistor. Have you tried measuring its resistance with a multimeter?
 

shrtrnd

Jan 15, 2010
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Harald identified them (again).
Jeez that guy is good.
They're very common in the older Hewlett Packard test and measurement instruments I work on.
 

hevans1944

Hop - AC8NS
Jun 21, 2012
4,878
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Could you tell us what kind of laser pulser you are examining? Is it a commercial laser diode pulser? Does it use a transistor operating in avalanche mode? What are you trying to do with your laser pulser? Optical radar (LIDAR) perhaps? Fiber optical communications? Please tell us what you are trying to DO?

Attached is some background information (somewhat dated now, but still a good read) on using a transistor in avalanche mode to obtain fast rising, narrow, optical pulses from a diode laser for use in a laser-ranging application. Bottom line appears to be you have to carefully select from any given lot of transistors the ones that have the proper characteristics for avalanche-mode operation. I would hope that some progress has been made since this paper was published to allow purchase of transistors specifically made for this purpose.
 

Attachments

  • Avalanche Laser Pulser.pdf
    119.5 KB · Views: 66

Johnny Lee

Oct 31, 2016
3
Joined
Oct 31, 2016
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Thank for all. I tried NDYAG Laser pulser in test lab. So, I try benchmark other countries products in my school. thanks again.
 
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