Reading an SM Resistor Code 820 vs. 028

[trag]

They're so tiny, I guess it's reasonable that the 2 looks the same right-side-up as upside-down, but grrrrr. I should just pull out the ohmmeter, but...

Anyone know off hand if 028 would be a valid resistor code? Seems like it would always be 207 and never 028, suggesting that these must be 820 resistors...

What do you think?

 

[trag]

And a 6 with an underline or a 9 with a dash over it? 562 or 295?

 

[max1zzz]

Resistior codes on SMT's are value, value, multiplier so 028 would not be a valid code, 820 is valid and would be 82 ohms (for fractional values it'll be written as value, R, value or R, value, value rather than having any leading zeros (R denotes the decimal point))

I have never seen a line under any characters on a SMT code but I would presume that it is suppose to be under the character so it should be 562. Also given that 562 would be 5.6K (56 x 100) which is a common value and 295 would be 2.9M (29x 100000) which would be a very uncommon value it seems that 562 is correct

If you see one with any letter other than R in the value it is one of the horrible modern codes you will need to find a lookup table to decode (I can never remember what the hell those damn codes mean....)

 

[trag]

Thank you, @max1zzz . With enough peering under magnification, I was eventually able to discern a difference between upside down and right side up on the '2's. A very subtle, squint and you'll miss it difference.

But it's nice to have confirmation that 028 would make no sense.

I ordered some 102 resistors and when they arrived they all appear to just have a dash in the center. There isn't even a 'modern code'. I don't know how anyone would discern the resistance without removing them from the circuit.

Less and less serviceable seems to be the future.

 

[max1zzz]

I ordered some 102 resistors and when they arrived they all appear to just have a dash in the center.

Some smaller components don't have markings on them at all (0402 size and smaller are usually unmarked) but some manufactures also don't mark larger components these days, I have some "large" 1206 sized resistors I brought recently that have no markings on them at all (I blame the manufacturer for being lazy!)

Less and less serviceable seems to be the future.

Indeed. I could go on a long and impressive rant about manufacturers soldering storage onto laptop motherboards...... But i'll leave that for another day!