Cap Values

Ive found some caps with writing on such as 225J and 224J, does this have any actual meaning to their value?

 

Not that I know of. All cap values are measured in Farad values (more usually fractions thereof) ie. pf, nf, uf etc (pico-farad, nano-farad and micro-farad)

 

It is probably a part number/code. If you know the make it may help you get the value.

 

Sadly I dont, theyre just unbranded breeds as for as I can tell. Ive got some of the values but theres a very fussy section populated by ceramics I need to find out who they are.

 

if i rember correctly 225 is 0.0000022 farad and 22 is 0.000022 farad

 

Do you know of any info about this?? Ive a schem for the valve section and 225 is 2.2uF and 224 is 0.22uf

 

22 x 5nothings picofarads = 2200000pF = 2.2uF

j = 5%

k = 10%

l = 20%

tho my memory is from a long time back too, so feel free to correct me.

edited:-

this numbering is nearly always on good film capacitor [thats why they advertise 5% tol]. I cant see why you would need to change them for others

 

Thanks Graham, does that percentage relate to tolerance of the cap?

 

It does. 5% is good for an off the shelf cap. Only limited types and values are available at 1%.

Film caps would not drift in value or age like an electrolyt cap. The only way to hurt them is over voltage - and they are probably 100, 200 or 500 volt rated

 

The numbers on surface mount resistors work the same way, should anyone be interested for future reference. IE "100" = 10 ohms, "102" = 1000 ohms, etc.

 

They are handling 30v max, Ive not fully worked it all out yet but thats the most there is. They are in the signal line so Im going to try something more 'audio'.

 

I never understood why they did that for caps etc. I can never remember that off the top of my head and have to go and look it up.

 

224 is definately 0.22uf, just replaced some nasty little ones in an amp yuk!!

 

Ive some nasty little ones in a pre amp Ive just got. What did you replace them with?

 

M-cap supremes, though they are quite large, excellent upgrade if you not shelling out on V-caps. Wm

 

to make things easier to read, is that a . or ground in dirt