Electrical – How to determine the model/type of SMD Capacitor and EMI Suppression Filters on a laptop PCB


I am a newbie to PCB electronic components and I have the following questions on SMD on a laptop PCB. The picture below shows the SMDs around a m.2 connector for SATA SSDs.

1) The SMD in the red rectangle are ceramic capacitors (earth colour with golden end connectors) ? And the ones in the green rectangles are EMI suppression filters (black colour with silver end connectors)?

2) How can I determine the type/capacity of these SMD and where can I find the catalogues of manufacturer on the net?

Thank you very much!

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Best Answer

1) Although it's difficult sometimes to tell, particularly from that picture, generally flatter black SMD components are resistors, while the taller brown ones are capacitors. However, there are exceptions to this.

2) Sites like Digikey.com and Mouser.com are where you purchase components from various manufacturers. You should ideally have the schematic for whatever circuit you're looking at to attempt changes or repairs; if a capacitor has failed short, for example, there is no other way to tell what its value is. If a component is still intact, you could remove it from the board and use a multimeter to test its resistance or capacitance; removal may not even be necessary depending on the circuit.

This being said, it sounds like you may not be ready for this level of electronics yet; EMI filters are frequently a combination of components used for a desired reduction of unwanted noise/emissions, rather than a type of component, although as The Photon has pointed out such components do exist.

I would suggest you do a lot more study and make at least a few boards or circuits of your own, becoming familiar with what different components look like and how they function, before trying to tackle complex SMD circuits like laptops.