What is this SMD component? - Electronic Circuits Projects Diagrams Free

TV-Engineer · 1st April 2005, 08:31 PM

Hello all,

Maybe someone could help identify a component for me?

It's from a laptop's charger board. There are two on there, both on the 19V input line, one straight after the 19V comes to the board, so the rest of the board is fed through this part. The other has a similar function on the other end of the board, where the charging circuitry is. They are designated RS1 and RS2. The second pic shows more of the board to give an idea on size and perspective of the part.

They are in plastic packages - the first one on the board had got hot and was bulging and inflated considerably, like a balloon ready to pop. Still read short, though. The one which is pictured and working fine measures just 0.5 ohms on the meter, which is actually 0 ohms, since just connecting the meter probes together gives me 0.5 ohms resistance...

So, that rules them out as resistors, despite the odd marking of 50 m(ohm sign) F. If they're fuses, it didn't go open despite passing enough current to heat it up and melt it, and they're like none I've seen of the SMD variety, and I wouldn't know the rating from the odd markings on them.

Any ideas anyone please?

Thank you.

**Nigel Goodwin** · 1st April 2005, 08:53 PM

I would presume they are resistors, and clearly marked with their values - 50 milliohms - or 0.05 ohms. Presumably they are used for monitoring the current taken?.

Styx · 1st April 2005, 09:42 PM

and that DPAK solder on on a skew

TV-Engineer · 1st April 2005, 09:52 PM

Thank you very much for your reply, they are indeed current-sensing resistors, and that one is 0.05 ohms as you said.

The exact ones can be purchased in the US at www.mouser.com (only $12 shipping to the UK for parts totalling under 4lbs in weight, very quick in getting here - <1 week for me - and the parts are cheap and SMD parts available in quantities of 1 and over for a change) for anyone who needs them. And here is the datasheet showing the identical part to the one in my picture:

http://www.koaspeer.com/koa/pdfs/SL1_SL2_SL3_TSL.pdf

made by Koa Speer Electronics.

Hope this info helps someone as much as the previous post has helped me. Thanks Nigel, I do appreciate your time and knowledge.

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1st April 2005, 08:31 PM	(permalink)
TV-Engineer	What is this SMD component? Hello all, Maybe someone could help identify a component for me? It's from a laptop's charger board. There are two on there, both on the 19V input line, one straight after the 19V comes to the board, so the rest of the board is fed through this part. The other has a similar function on the other end of the board, where the charging circuitry is. They are designated RS1 and RS2. The second pic shows more of the board to give an idea on size and perspective of the part. They are in plastic packages - the first one on the board had got hot and was bulging and inflated considerably, like a balloon ready to pop. Still read short, though. The one which is pictured and working fine measures just 0.5 ohms on the meter, which is actually 0 ohms, since just connecting the meter probes together gives me 0.5 ohms resistance... So, that rules them out as resistors, despite the odd marking of 50 m(ohm sign) F. If they're fuses, it didn't go open despite passing enough current to heat it up and melt it, and they're like none I've seen of the SMD variety, and I wouldn't know the rating from the odd markings on them. Any ideas anyone please? Thank you. __________________ I don\'t claim to know everything... I just want to know everything.

1st April 2005, 08:53 PM	(permalink)
Nigel Goodwin	I would presume they are resistors, and clearly marked with their values - 50 milliohms - or 0.05 ohms. Presumably they are used for monitoring the current taken?. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

1st April 2005, 09:42 PM	(permalink)
Styx	and that DPAK solder on on a skew __________________ Nothing is impossible. Once a problem is realised, the rest is just details

1st April 2005, 09:52 PM	(permalink)
TV-Engineer	Thank you very much for your reply, they are indeed current-sensing resistors, and that one is 0.05 ohms as you said. The exact ones can be purchased in the US at www.mouser.com (only $12 shipping to the UK for parts totalling under 4lbs in weight, very quick in getting here - <1 week for me - and the parts are cheap and SMD parts available in quantities of 1 and over for a change) for anyone who needs them. And here is the datasheet showing the identical part to the one in my picture: http://www.koaspeer.com/koa/pdfs/SL1_SL2_SL3_TSL.pdf made by Koa Speer Electronics. Hope this info helps someone as much as the previous post has helped me. Thanks Nigel, I do appreciate your time and knowledge. __________________ I don\'t claim to know everything... I just want to know everything.