Author Topic: Identify SMD component with one dot  (Read 1279 times)

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Offline SHJH-13Topic starter

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Identify SMD component with one dot
« on: January 19, 2022, 01:02:57 pm »
Hello,

On this board I'm trying to make sense of there is a component, similar to an SMD resistor (maybe as big as an 805), but with only one circular dot. the dot is closer to one pad. I have searched a little, but the closest I've come to an answer is:

https://www.eevblog.com/forum/beginners/identify-smd-components-one-with-a-square-dot-other-iridiscent/.

However, the component in the mentioned post has a square dot in the center. I doubt that my component is a jumper.

I appreciate your help and advice.
 

Offline w2aew

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Re: Identify SMD component with one dot
« Reply #1 on: January 19, 2022, 03:38:44 pm »
It might possibly be a diode of some sort.
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Offline golden_labels

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Re: Identify SMD component with one dot
« Reply #2 on: January 19, 2022, 03:45:28 pm »
I support w2aew’s identification. The dot indicates some kind of assymetry and there are two groups of common two-lead assymetric components: diodes and capacitors. A polarized radial capacitor of that size is unlikely, so the guess about the diode seems reasonable.

Reverse-engineering the circuit would be a good idea, as that may reveal the function of the component.
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Offline SHJH-13Topic starter

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Re: Identify SMD component with one dot
« Reply #3 on: January 22, 2022, 06:26:32 am »
Yes, a diode was my first guess as well, however, there are two issues with that which makes me believe it might be something else.

1- This is a PIM-sensitive device and having an active component should theoretically increase PIM.
2- There appears to be no possible point for biasing the diode. The only possible path is blocked by a capacitor.

Thank you for your response.
 

Offline PKTKS

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Re: Identify SMD component with one dot
« Reply #4 on: January 22, 2022, 08:34:08 am »
I would guess a TVS some sort..

Have been replaced some on laptops..
Any way to find reference is schema..

Paul
« Last Edit: January 22, 2022, 09:22:08 am by PKTKS »
 

Offline rpiloverbd

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Re: Identify SMD component with one dot
« Reply #5 on: January 24, 2022, 12:35:41 pm »
Looks like an SMD diode. Have you checked with a multimeter?
 

Offline John.S

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Re: Identify SMD component with one dot
« Reply #6 on: January 25, 2022, 12:47:48 pm »
Hi

From the time (long-long ago) I made my own FM transmitters I recognize this component as a Varicap.
The white dot indicates: White: BA512, 515, BB515, 811

Hope this helps.
gr. John.
Don't think in problems, think in solutions....
 


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