Author Topic: SMD Component Identification Help  (Read 546 times)

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Offline TesttechTopic starter

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SMD Component Identification Help
« on: December 21, 2024, 10:19:19 pm »
Greetings,

I am working on an RF circuit and have encountered SMD components that I do not recognize. Please see the picture. I have outlined the four parts in question.
They have white translucent bodies, no marking other than the partial black band.
Resistance measured across these varies, and I suspect that the reading are from other circuit DC paths. I suspect capacitors.

Does anyone know for certain?

Thank you!
 

Online fzabkar

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Re: SMD Component Identification Help
« Reply #1 on: December 21, 2024, 10:44:26 pm »
The unmarked ones look like chip inductors. If so, then they should measure close to zero ohms.
 

Offline TesttechTopic starter

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Re: SMD Component Identification Help
« Reply #2 on: December 21, 2024, 10:48:52 pm »
I don't think they are inductors, as some measure in the 1000's of ohms, and other do not.
 

Online fzabkar

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Re: SMD Component Identification Help
« Reply #3 on: December 21, 2024, 11:56:56 pm »
Precision resistors?
 

Offline TesttechTopic starter

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Re: SMD Component Identification Help
« Reply #4 on: December 23, 2024, 12:17:10 am »
fzabkar,

You are correct, these are inductors!
 I am in the process of working out exactly what is going on. Some of these components have clearly failed open circuit. Unfortunately, there are no value markings, so I am not sure how to estimate the correct values.
Some are in the signal path, (3-4 GHz), others seem to be bias filters for the transistor gain stages.
 

Offline eb4fbz

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Re: SMD Component Identification Help
« Reply #5 on: December 24, 2024, 11:40:57 am »
Multilayer inductors
 

Offline u666sa

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Re: SMD Component Identification Help
« Reply #6 on: December 24, 2024, 12:14:30 pm »


Which one is open circuit?
 

Offline TesttechTopic starter

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Re: SMD Component Identification Help
« Reply #7 on: December 24, 2024, 07:41:36 pm »
More progress with the component identification.

The components in question are both inductors and microwave capacitors. Unfortunately they appear almost identical, and have no value marking.

The inductors have a black square located at one end, while the capacitors have a black square in the middle of the white body.

I drew the schematic and it became clear that the capacitors are connected from a DC point to ground, or in a series signal path, (3.5 GHz), while the inductors are essentially bias chokes.

It looks like the RF transistor is dead, replacement on order.

Thanks to all who have responded.
 


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