what led

[Bobster]

When I designed some LED power supplies I couldn't really do them properly for under £10 for just the parts, probably end sale price of over £30. One of the high temperature essential capacitors was £1.50 even in bulk, though a lower quality would fail in a year replacement was 11pence !!!. Could have cut corners used cheaper lower quality, low temperature rated parts but then power supply lifetime will suffer and be significantly less than the LED !!!

I think maybe you need to change your component suppliers or your designs! You simply shouldn't need expensive capacitors like that in such a simple design, or you are being ripped off.

 

[ian_m]

I think maybe you need to change your component suppliers or your designs! You simply shouldn't need expensive capacitors like that in such a simple design, or you are being ripped off.

Not so. There are some very clever efficient designs that use aluminium polymer electrolytic capacitors as their main switching capacitors. These have the required long life, industrial temperature rating and required electrical characteristics, to match the PSU chip used. There was a "famous" article by EDN magazine that examined loads of LED fixtures working and failed, and the lifetime of the design was absolutely nothing to do with LED's or active components but purely down to the lifetime of the capacitors used, generally cost shortcuts being taken and producing an LED bulb with LEDs rated for 50,000hours failing after 1000hours due to passive component failure. Until LED lights came along failure and lifetimes of capacitors was something designers didn't pay much attention too, generally before this the electronics failed before the capacitors.

This was used @ £1.75 each. Obviously a reel was much cheaper about £0.50 each, but still a substantial part of the cost.
http://uk.farnell.com/panasonic/16svpf560m/cap-alu-elec-560uf-16v-smd/dp/2354791?ost=2354791