Best practices and how to when measuring SMD components

Thread Starter

Lumenosity

Joined Mar 1, 2017
636
Hello,

Today I am working on reproducing another PCB. This one has quite a few SMD components on it.

The issue I am running into is trying to get an accurate measurement of the various SMD resistors on the board.

I am using a standard run of the mill (inexpensive) 150mm Digital caliper. Which may be the problem?

In any event, the resistors are so small that I find it very difficult to differentiate between 0603, 0805 and 1206 size resistors for example.

I am wondering how you accurately determine the size of SMD resistors on a PCB? Do you have to remove them to measure them accurately?

What tool is best for this?

As always, thanks for your help.
 

MrChips

Joined Oct 2, 2009
24,616
Hello,

Today I am working on reproducing another PCB. This one has quite a few SMD components on it.

The issue I am running into is trying to get an accurate measurement of the various SMD resistors on the board.

I am using a standard run of the mill (inexpensive) 150mm Digital caliper. Which may be the problem?

In any event, the resistors are so small that I find it very difficult to differentiate between 0603, 0805 and 1206 size resistors for example.

I am wondering how you accurately determine the size of SMD resistors on a PCB? Do you have to remove them to measure them accurately?

What tool is best for this?

As always, thanks for your help.
You ought to be able to tell the difference in sizes by visual inspection.
If you are trying to replicate the board all you need to know is the value or ID of the component.
You can stick with one size such as 0805 unless voltage or power is an issue.
 

Thread Starter

Lumenosity

Joined Mar 1, 2017
636
You ought to be able to tell the difference in sizes by visual inspection.
If you are trying to replicate the board all you need to know is the value or ID of the component.
You can stick with one size such as 0805 unless voltage or power is an issue.
Hello,
The other issue is space on the board.
It's pretty tight in some places.
 

dl324

Joined Mar 30, 2015
13,510
In any event, the resistors are so small that I find it very difficult to differentiate between 0603, 0805 and 1206 size resistors for example.

I am wondering how you accurately determine the size of SMD resistors on a PCB? Do you have to remove them to measure them accurately?

What tool is best for this?
Once you get used to working with them, you can tell with a glance. Until you get to 0201, the numbers represent length and width in mils.
 
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