Capacitor Letter?

[Dean Huster]

Capacitor tolerance letter codes

I, too, have never seen anything in writing, but have tended to assume that under 100pf, the value is read directly. In that case, the code will always use two digits and a letter, e.g., "47K" which would decipher as 47pF, 10%. A lot of unknowing folks want that "K" to be a multiplier, compounding the confusion.

It's also difficult to find the letter codes for the tolerances all in one place. I've collected together all that I've found and here's that list:

B = ±0.1pF
C = ± 0.25pF
D = ±0.5pF
E = ±0.25%
F = ±1.0pF
G = ±2%
H = ±2.5%
J = ±5%
K = ±10%
L = ±15%
M = ±20%
N = ±30%
P = -0, +100%
S = -20, +50%
W = -0, +200%
X = -20, +40%
Z = -20, +80%


Dean

 

[kinjalgp]

Great! Never seen so may tolerance codes before.

Just thinking of "P = -0, +100%". It has 100% tolerance so you can never trust that capacitor.

 

[Dean Huster]

Bulk capacitance

Kinjal, those last few tolerances that express a small negative tolerance and larger positive tolerance are most generally placed upon capacitors used as "bulk capacitance". These are capacitors where the value doesn't really matter that much, but more is better than less. A typical application would be for power supply decoupling capacitors and filter capacitors.

Dean

 

[kinjalgp]

Thanks for the information.