ponderings on the shortage of capacitors

[rob_croxford]

A few days ago I was asked to fault find and repair an old board from a heater controller. After finding the problem my next job was to order the components in order to carry out the repair. It was a relatively generic list of components, a transformer, a few diodes and some capacitors. All was going well until i tried to order the capacitors (0.47uF plastic film) which had a lead time of 40 weeks!! As luck would have it i had a few of these relativly common capacitors in my odds and sods box. However it did lead me to wondering why, especicially these types of capacitors, were so hard to come by.

Im sure we have all heard of the tantalum shortages leading to massive lead times on tantalum capacitors, and even the aluminium film shortages which altho there is an abundance of the stuff just simply wasnt manufactured to demand. This could account for the shortages of plastic film caps down to the use of aluminium film within them however 40 weeks still seems like a long time for such a common alloy.

So, does anyone have any insight on this matter??

All the best

 

[Resqueline]

I'm surprised to hear that, but I wonder if it's universal and not just one specific brand/type from one supplier. Did you try to look around for other brands/suppliers?
I've been informed btw. that the metal on the plastic film in those cap's is not aluminum - but zinc..

 

[rob_croxford]

Yes i have tried a variety of manufactures the only information they will give me is that there is a shortage at the moment and lead times are extended.

Zinc - wow i always thort it was aluminum.

The only conclusion i have really come to myself is in the process of plating the zinc with the plastic. as far as i understand this "plating" or "insulating" process has to be done within a type of plasma in order to ensure a even covering of the metal. I can imagin this type of process to be time consuming and relativly expensive. Other than that perhaps people are trying to replace Tantalum capacitors with plastic film however i cant think of many applications that this would be appropriate. There is talk of higher grade aluminium being used in electrolytics to replace the Tantalum however im not really sure how far in the pipe line this is.

Another thing that astounded me was the price of these capacitors. For the 0.47uF caps i needed the price sat at arround 35 pence each with no price break, regardless of how many you bought.

 

[Resqueline]

Huh, general shortage, imagine that..

Yes, I was surprised to learn about the use of zink too. I haven't double-checked it but it could add up by the looks of a roll of film lying open for years in my basement.

Repairing psu's I always replace stressed 0.47-4.7uf electrolytics with plastic film for durability but I can't imagine manufacturers going by anything other than price..
Strange world.. But on the other hand I must say that the component manufacturers so far have been good at supplying the needs of the world w/o creating shortages.

Hard for a layman to guess at what factors have been at work here. Anyway, with a real & bad shortage I'm not surprised the price breaks have disappeared..

 

[(*steve*)]

I am even more glad that I purchased quite a number of reels of tantalum and ceramic surface mount capacitors when companies started almost throwing them out at the beginning of the financial meltdown.

Buying a reel for what I would normally pay for 20 to 50 components seems like an even better deal now (if that can be imagined).

I wonder if some of that demand is companies re-stocking after selling "excess" stock at fire-sale prices?

 

[TheLaw]

http://www.mouser.com/Passive-Compo...ypropylene-Film-Capacitors/_/N-5g7u?P=1z0wqua

How about some of these? Don't fit the bill?

 

[rob_croxford]

You could be right there Steve, this could be a stock issue. Perhaps manufactuers simply havent recovered - which leads to the hopes that this issue should be resolved soon (at least for anything but tatalum). This would also explain the dramatic price increases. However it does lead you to wonder why supply of such an important and common component has been allowed to break down. It is my custom to expect large lead times when ordering things such as high end IGBT modules or large hocky puck Thyristors. But this is all acounted for as long lead times are forewarned. But with no apparent warning for this lack of common capacitors it would be interesting to know how hard small suppliers and manufacturing companies have been hit, especially with the price increasing from > or no more than a couple of pence by 50% in some cases.