# Value Identification of a resistor in a circuit Diagram

#### Deltatango

Joined Apr 16, 2012
16
I am working on a power supply "freehand" no manual so am searching for value clues from the internet of similar designs and come across a reference I am unsure of:-

A resistor that is marked 2E along with other resistors ending with the "E" prefix if anyone can help me that would be great....

Many Thanks from David

#### Irving

Joined Jan 30, 2016
2,550
Good close up pictures would help.

Normally there would be 2digits + a letter so 02E would be 1.02Mohm (SMD Resistor marking), but 2E is unusual. Are you sure its a resistor and not some other device? It could be an SMD Fuse, 2E might be 2A slow blow. It could also be a zener diode.

#### Deltatango

Joined Apr 16, 2012
16
The marking I describe is Not on the device (which is a blown up smd about 8 to 1206 size) its on a circuit diagram, along with other similar resistor markings like 4.7E etc, my feeling and logic in respect of circuit positions is its R but I want to be sure.

Thank you so far

David

#### Irving

Joined Jan 30, 2016
2,550
Oh right. On the schematic it almost certainly means "ohm".

#### Deltatango

Joined Apr 16, 2012
16
Yes I feel that it would be but I tend to be a bit dogged to find the answer to what E stands for, Epsilon or some other word??

David

#### Ramussons

Joined May 3, 2013
1,228
E = Ohms.

#### Deltatango

Joined Apr 16, 2012
16
To cover all bases I asked RS for a view on on this below is part of their response :-

Dear David.

Thank you for your recent enquiry.

For resistors E can be the same as Ω. It is often used in case of high power resistors (power not being less than 5W). Sometimes you can see R written instead of E.
We are however unable to determine the ohms or power rating of the required resistor form an E2 reference.

So from this I accept that "E" = "R" my only thought is who started it and why? one day may learn......