Diode Id code?

[Doomguy42]

Hi there I struggle with Id's I've got some diodes in a psu I'm looking at marked-
1n40038.
Is this a different component to 1n4003? I can never tell what all the extra digits are for?

 

[ronsimpson]

There is a 1N4003 diode. The size looks right. 1A, 200V.
The numbers and letters after the part number usually are a date code.

 

[Doomguy42]

Thank you, as a rule how do you differentiate? Just experience?

 

[ronsimpson]

In a large part each thing is on a different line.
On small parts it gets pushed together.
Some times you need to know what the part is to find what the part is. Example: the part number is XYZ-52, you need to know the part number is XYZ so you can find the data sheet so you can find out the -52 is for the part in a plastic case while -51 is for the metal case. Or maybe -44 is for the new version while -41 is the old version.

So yes experience.
Start typing on a search engine very slowly. "1N4" gets to many things but several types of diodes. "1N400" gets to 1,2,3,4,5,6,7 diode etc. "1N4002" get to diode 1A, 200V. You can learn from the internet.

 

[Mickster]

To add to Ron's post above, look out for datasheets in a search engine page.
In this case, 1N400.. will tend to give a common datasheet for a number of similar components, that have different ratings.
What looks like a 'B' might be something else, such as an '8', or vice versa.
This datasheet might help to explain your diode markings:

https://www.diodes.com/assets/Datasheets/ds28002.pdf

Look to the "Ordering information" table and you will see that the 'B' denotes a bulk purchase and a 'T' denotes a tape reel.

 

[Doomguy42]

Huge thanks for the Replies gents. As an amateur I just look at the codes and take that as gospel foe a whole part number Thanks for the tips... hopefully I'll understand more as I go on.