Surface mount capacitors

[Peter Daniel]

Originally posted by contaxchen

What should I do?

Just connect two of them to PS. One cap with dark bar on positive, one cap with dark bar on negative. The one that explodes wasn't connected properly You might put them in some container to avoid any risk.

On tantalum caps dark bar means +

[peranders]

Why don't you look in the datasheet?

Normally the plastic foot has two cut corners = plus

some sort of stripe at the can = negative

Let me also point out that SMD parts are made for machine soldering.

[Stocker]

Speaking of drilling holes unless it's for cell phones... I just read an article in a trade magazine discussing relative merits of bonding wire to terminals on the ICs that are stacked FOUR and FIVE tall inside cell phones

anyhow- On some of our PCBs here at work, the surface mount caps have a stripe on one side that is oriented toward a "+" printed on the PCB.

HTH

[ingvar ahlberg]

[i]

anyhow- On some of our PCBs here at work, the surface mount caps have a stripe on one side that is oriented toward a "+" printed on the PCB.

HTH [/B]

That is a tantal cap, electrolytics are always marked on negative side, some oscon types marked with + and -.

[Stocker]

what a headache! at least it's possible to tell them apart.

[contaxchen]

hello,

Let me also point out that SMD parts are made for machine soldering.

yes, but for sanyo OScon, you can pull its twe legs straight and solder the cap on PCB. Their quality seems better than the ones with soldering lugs. I am surprised by it superb metal finish. Nice sense of touching.

It's useless to tear them apart.... I have checked out the structure diagram. The anode is almost symmetric to its cathode. really!

Also, I don't think it gonna blow up if you reverse the positive and it negative. At most, the wrong positioning shorten the cpas life.

That's it.
CC

[contaxchen]

OK!!
The marked side is the cathode! This is the final conclusion after reviewing several SMD caps manufaturer's website.
C.C.

[jackinnj]

Originally posted by ingvar ahlberg
The "toaster oven" method is´nt really right for smd soldering, for reflow soldering You need an extremely tight control of heat curve: preheating to activate flux in paste- reflow- rapid cooling.

Well, it might not be "right" but it works, saves a lot of time and real estate. It's much easier to remove smd parts, and it's easier to prototype.

[Ralphono]

Originally posted by ingvar ahlberg The "toaster oven" method is´nt really right for smd soldering

For SMD rework at work we use a hot-air heat gun at about 400°C with special flux. This method makes out beautiful shiny melted tin. Just place the parts into the paste and look the melting tin. Remove the hot air if the tin is melten completely. You can solder part by part with this method.

You can also solder SMD parts per hand - 0,2mm pitch is possible - although i got an hurting red eye after 500 pins .

Greetings Ralphono

[djQUAN]

I also use the hot air soldering equipment. comes useful for shrink tubing too.

I only use hot air for resistors, IC's, transistors, ceramic caps. I always think electros and tants hate high temps.