Component Identification? What are these?

**eccerr0r** · 12-22-2012, 02:29 AM

I pulled these from somewhere a long time ago and never took a look at what they were. It's too bad that I didn't study the board they came out of, but the board's long gone... anyway, now I wonder if anyone knows what these are...

When I put an ohmmeter across them they're open both ways. I suspect they're kind of broken but maybe they're nonlinear...

**trebo** · 12-22-2012, 03:24 AM

could be zenner diodes,at a guess

Blargh523 · 12-22-2012, 03:37 AM

Quote:

Originally Posted by trebo

could be zenner diodes,at a guess

That would be my guess as well. I'm just not used to seeing color-bands on through-hole ones.

And good luck figuring out value, AFAIK, manufacturer's didn't really have a standard -- the colors don't translate directly to a voltage value, but to a part number on a look-up sheet -- which is why in most cases color-coded diodes have been replaced with ones with part numbers on them.

**Phaihn** · 12-22-2012, 03:47 AM

Quote:

Originally Posted by Blargh523

That would be my guess as well. I'm just not used to seeing color-bands on through-hole ones.

you mean see through or through hole?

Blargh523 · 12-22-2012, 03:52 AM

Quote:

Originally Posted by Phaihn

you mean see through or through hole?

Through-hole as opposed to surface-mount (SMT).

**Phaihn** · 12-22-2012, 03:54 AM

Quote:

Originally Posted by Blargh523

Through-hole as opposed to surface-mount (SMT).

ok

**eccerr0r** · 12-22-2012, 10:37 AM

They really do not look like diodes through the glass, but then again who knows... usually there's a visible whisker or orange like the one Blargh posted.

The fact that they're open both ways is bothersome, unless all four of them were fried at the same time... Very weird. A zener diode works like a regular diode when forward biased.

The internal construction of these things look like resistors more than semiconductors which bothers me... but then again they may be fried...

**Evil Lurker** · 12-22-2012, 01:41 PM

I have seen those before on CRT monitors/tvs on the small driver board that physically connects to the tube pins. Also I have seen similar looking devices on the mains input on some circuit boards. I have no clue what they are either... the only hint is the board is marked "SGXXX" wherein the x's are like any other component numbers.

**Longbow** · 12-22-2012, 03:01 PM

I believe these may be transient voltage suppressors, known as TVS diodes. These parts will test open until the rated voltage is exceeded. They come in either mono-directional or bi-directional types. The new ones I have are all in the standard black diode package however.

**retiredcaps** · 12-22-2012, 03:06 PM

SG is spark gap.

http://img.diytrade.com/cdimg/605332..._Spark_Gap.jpg

http://en.wikipedia.org/wiki/Spark_gap

**tom66** · 12-22-2012, 03:10 PM

Definitely minature spark gaps.

**ben7** · 12-22-2012, 03:43 PM

Quote:

Originally Posted by tom66

Definitely minature spark gaps.

Yeah, the definitely are.

I have some too. They work like neon lamps, they glow orange at about 80v. They look like the OP's too.

12-22-2012, 03:24 AM	#2
trebo Badcaps Veteran Join Date: Feb 2010 City & State: Cardiff My Country: Wales, UK Posts: 512	Re: Component Identification? What are these? could be zenner diodes,at a guess

12-22-2012, 10:37 AM	#7
eccerr0r Solder Sloth Join Date: Nov 2012 City & State: CO My Country: USA Line Voltage: 120VAC 60Hz I'm a: Hobbyist Tech Posts: 5,084	Re: Component Identification? What are these? They really do not look like diodes through the glass, but then again who knows... usually there's a visible whisker or orange like the one Blargh posted. The fact that they're open both ways is bothersome, unless all four of them were fried at the same time... Very weird. A zener diode works like a regular diode when forward biased. The internal construction of these things look like resistors more than semiconductors which bothers me... but then again they may be fried...

12-22-2012, 01:41 PM	#8
Evil Lurker Warranty Voider Join Date: Feb 2011 City & State: West Tennessee, USA Posts: 452	Re: Component Identification? What are these? I have seen those before on CRT monitors/tvs on the small driver board that physically connects to the tube pins. Also I have seen similar looking devices on the mains input on some circuit boards. I have no clue what they are either... the only hint is the board is marked "SGXXX" wherein the x's are like any other component numbers.

12-22-2012, 03:01 PM	#9
Longbow Badcaps Veteran Join Date: Jun 2011 City & State: Brighton, U.K. Posts: 620	Re: Component Identification? What are these? I believe these may be transient voltage suppressors, known as TVS diodes. These parts will test open until the rated voltage is exceeded. They come in either mono-directional or bi-directional types. The new ones I have are all in the standard black diode package however. __________________ Is it plugged in?

12-22-2012, 03:06 PM	#10
retiredcaps Badcaps Veteran Join Date: Apr 2010 City & State: Canada Posts: 9,163	Re: Component Identification? What are these? SG is spark gap. http://img.diytrade.com/cdimg/605332..._Spark_Gap.jpg http://en.wikipedia.org/wiki/Spark_gap __________________ --- begin sig file --- If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post. We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings. Please do not post inline and offsite as they slow down the loading of pages. --- end sig file ---

12-22-2012, 03:10 PM	#11
tom66 EVs Rule Join Date: Apr 2011 City & State: Leeds My Country: UK Line Voltage: 230Vac 50Hz I'm a: Professional Tech Posts: 32,373	Re: Component Identification? What are these? Definitely minature spark gaps. __________________ Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead! Free service manuals: http://www.toms-service-manuals.com/ -- 72 LED/LCD TVs, 5 monitors, 28 plasma TVs, and 2 AVR 6.1 amplifiers fixed! -- I repair Pioneer 9G Plasma Main Boards & KRP-M01 Media Receivers (PM me for info) 2 Pioneer KURO 9G, 12 Panasonic LCD/Plasma, 1 Sony LCD, 1 NEC Plasma, 2 Yamaha HTS, 5 Sharp LCDs, 5 Toshiba LCDs, 7 Philips Plasma/LCD, 1 Hitachi Plasma, 11 LG LCD/Plasma, 18 Samsung LED/LCD/Plasma, 1 Thomson Plasma, 1 Atec LCD, 1 Hanspree LCD, 1 Xerox LCD, 1 Harwa LCD, 2 Proview LCD, 2 Hyundai LCD, 1 "Onn" LCD, 1 Grundig LCD, 1 Dell LCD, 1 iiyama LCD, 1 Acer LED, 1 Logik LCD, 1 Baird (China) LCD, 6 Bush LCDs, 22 Vestel LCDs (Best->Worst)

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