Identify SMD capacitor types visually?

CHRIS8

Disabled Account
2001-12-12 8:47 am
VA, USA
Is their a way to visually identify a surface mount capacitor dielectric, such as by case color of the capacitor?

Forgive my ignorance, but I have practically no experience with SM, and the data that I have found on the net does not mention any specific information concerning case color. Is capacitor case color also largely irrelevant in the SM world?

-Chris
 
SMD caps

Most of the surface mount caps are either ceramic or tantalum electrolytic. the ceramic caps are usually too small to have markings. The tantalums will have a polarity band or some indication of polarity. They might be marked with a couple of numbers if big enough, the capacitance in uF and the voltage.

H.H.
 
SMD caps

SMD tantalums usually have enough room to have the value and voltage spelled out. Most SMD ceramic caps are not marked! Since most are much smaller than a grain of rice there is not much room on them for marking. I just spent three years designing line cards for telecom using SMD devices. Film caps are large enough for markings but usually only the european made caps are consistently marked for dielectric type.

H.H.
 
How to identify SMD capacitors :
- Ceramic capacitors : generally small, greyish or brownish body with metallized edges, generally unmarked -> capacitance meter !
Values under 1nF generally are C0G dielectric (high quality), higher values are X7R, Z5U, etc, good enough for supply bypass... Color is generally greyish for C0G and brownish for other dielectrics, but the size is a guide : a small cap with a large value cannot have a good dielectric...
- Tantalum : most are molded , black or sand body, marked value/voltage, band identifying positive polarity, electrodes are formed metal. Some are unmolded with an orange body, metallized electrodes, positive having a protruding bar, value not marked.
- Electrolytic : Most are miniature standard types with a plastic base and formed wires, value marked, band identifying negative polarity.
Hope this will be useful...;)
 

Havoc

Member
2002-02-06 9:16 pm
As far as all those I saw concerned, the gray ones are mostly C0G, light brown X...R, and darker ones Z5U or Y5T. Just never mix them up!

For serious work, do not go below X5R. And do not go below 0805 package. Larger packages than 1812 are also to avoid for diy. The small ones because of the difficulty soldering and the lousy dielectrics. These very high C/V ratios tend to become piezo-electric. The large ones are fragile.
 

CHRIS8

Disabled Account
2001-12-12 8:47 am
VA, USA
Thanks to all for the great information concerning smd capacitors.

Just so you know, the capacitors in question were in the signal path in a crossover. They are unmarked badge-brown tone color and about 3x bigger than a 1/8 watt smd resistor. They are all about 470pF. I was simply wondering if I could tell what type of capacitor these were, and if it was a really cheap cap that i should perhaps change out with a better dielectric.

According the information I have heard, these would seem to fit the bill of a decent dielectric otherwise they would certainly be a smaller size physically.

Thanks.

-Chris
 
Most likely, it's a ceramic cap and the value info is only printed on the reel it's from not each component. It will need to be measured. You might obtain some "series" type info from the physical size of the cap, but otherwise it can't be "read" as with thru-hole parts.

edit: If you go to this link you'll find a free pdf review of a component identification guide. Through-hole and surface mount.
 
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