"Surge Suppressor Diodes"...??

redrabbit · 29th August 2007, 02:15 AM

"Surge Suppressor Diodes"

What are the purpose of these?
I have several NOS that were bought in an ebay "lot".

One for instance is 44v (bv) 250 mA .

=RR=

redrabbit · 29th August 2007, 02:28 AM

The diodes I have are older, no data sheets.

But are "Surge supp.....diodes" and "Transient supp....diodes", the same?

like in this application?...

http://relays.tycoelectronics.com/ap...fs/13c3311.pdf

=RR=

thomas997 · 29th August 2007, 11:42 PM

Basically high power zener diodes used for over voltage protection.

So if I have a 40V device, and I want to be sure it doesn't receive a huge/quick spike on its supply, you can put it reverse biased from supply to gnd.

The one you have sounds somewhat low rated (11W). Depends on what that rating is though (continuous or short pulse) and how large it is.

You can find modern TVS zeners at 600W or more in small packages. Uni or bi-directional (test with diode function on meter).

http://www.ce-mag.com/archive/01/Spring/Lee.html

AndrewT · 30th August 2007, 12:16 AM

Hi,
these are usually intended to reduce the very short term transients that get through the transformer and past the smoothing caps.
They cannot accept long term conduction. They will overheat.

davefromnj · 13th September 2007, 04:12 AM

Specifically TVS diodes look electrically like two high power zener diodes cathode to cathode with their annodes exposed.

They act exactly in the same was as an MOV Varistor, except that they are much more precise (a 30V MOV may actually trigger at 68V, whereas a 30V TVS will trigger at up to 33V.) They are intended only for surge supression, usually for UL, CSA or IEC compliance testing.

They typically are placed across ANY field wiring circuit and from each field wiring terminal to earth ground.

They do have capacitance which needs to be examined very carefully if you intend to use them across high-speed data lines, including RS-485 and the like.

29th August 2007, 02:15 AM	#1
redrabbit diyAudio Member Join Date: Oct 2004	"Surge Suppressor Diodes"...?? "Surge Suppressor Diodes" What are the purpose of these? I have several NOS that were bought in an ebay "lot". One for instance is 44v (bv) 250 mA . =RR=

13th September 2007, 04:12 AM	#5
davefromnj diyAudio Member Join Date: Sep 2007	Specifically Specifically TVS diodes look electrically like two high power zener diodes cathode to cathode with their annodes exposed. They act exactly in the same was as an MOV Varistor, except that they are much more precise (a 30V MOV may actually trigger at 68V, whereas a 30V TVS will trigger at up to 33V.) They are intended only for surge supression, usually for UL, CSA or IEC compliance testing. They typically are placed across ANY field wiring circuit and from each field wiring terminal to earth ground. They do have capacitance which needs to be examined very carefully if you intend to use them across high-speed data lines, including RS-485 and the like.

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29th August 2007, 02:28 AM	#2
redrabbit diyAudio Member Join Date: Oct 2004	The diodes I have are older, no data sheets. But are "Surge supp.....diodes" and "Transient supp....diodes", the same? like in this application?... http://relays.tycoelectronics.com/ap...fs/13c3311.pdf =RR=

29th August 2007, 11:42 PM	#3
thomas997 diyAudio Member Join Date: Feb 2004 Location: Vancouver	Basically high power zener diodes used for over voltage protection. So if I have a 40V device, and I want to be sure it doesn't receive a huge/quick spike on its supply, you can put it reverse biased from supply to gnd. The one you have sounds somewhat low rated (11W). Depends on what that rating is though (continuous or short pulse) and how large it is. You can find modern TVS zeners at 600W or more in small packages. Uni or bi-directional (test with diode function on meter). http://www.ce-mag.com/archive/01/Spring/Lee.html

30th August 2007, 12:16 AM	#4
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, these are usually intended to reduce the very short term transients that get through the transformer and past the smoothing caps. They cannot accept long term conduction. They will overheat.