Built up a pcb with a couple of leds in it.
Red led came on fine not the green one.
Went through pcb looking for open circuit but it was fine.
Then just out interest I turned the led around and it came on.
Seem to have bought some leds with short lead the positive one.
First time I have seen that in 40 years in electronics !
I have had a couple of one legged capacitors before though.
Red led came on fine not the green one.
Went through pcb looking for open circuit but it was fine.
Then just out interest I turned the led around and it came on.
Seem to have bought some leds with short lead the positive one.
First time I have seen that in 40 years in electronics !
I have had a couple of one legged capacitors before though.
I have bought 1N4002 and 1N5402 with the white band at the wrong end.
Otherwise working perfectly well.
Just curious: what about the flattened plastic side showing cathode?
Was it also wrong?
Since I often pre clip to size or bend LED legs, I trust it better than just leg length, go figure.
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Lead length is not, nor ever has been, a polarity indicator on an LED. That's the purpose of the flat on the body. (Think about it - once soldered to a board how could you use lead length to check polarity?).
Having leads of different lengths is a convenience for hand-assembly only. Many manufacturers have settled on the same de-facto standard for this, but not all it appears - the ratio is at least 90%--10%, so many people infer its a polarity indicator until they encounter the exceptions.
I have been in electronics for 40 years and never had an LED with short lead the positive one. I remember it like electrolytics where long lead goes to positive.
HP doesn't make LED's anymore. Those had a datasheet. Also some consistency.
These generic LED's I'm buying, even from farnell, no datasheet & I can't tell if the design current is 10 ma or 20. A bag of LED's from parts-express with resistors "for 5 v or 12 v", came with resistor values for 20 ma. Farnell didn't sell round ones anymore, and no red for SS amp bias. Cutting 2 rectangular holes in a faceplate is a P*** with a needle file.
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We get only round ones here, very cheap, about 100 for a dollar in red. green or yellow, 5 mm
White, blue and 3 mm are more expensive.
Flat ones are hard to get....so are the old dim ones, now all super (or too) bright.
White, blue and 3 mm are more expensive.
Flat ones are hard to get....so are the old dim ones, now all super (or too) bright.
The day I was buying my speaker protector project, newark US had red+green 3 lead LED in rectangular package, and yellow LED in a different rectangular package. No red at all. I don't buy things every day, it takes $9 to get a box from newark or digikey and $15 to get a box from mouser. Under $?? order there is a handling fee. That is why I bought a 100 multicolor led assortment from part-express later, they came in a $7 box already filled with other stuff.
What newark has today may vary. I bought 1/8 stereo phone recept to 1/4" stereo plug adapters from newark 18 months ago. the burglar carried them and all other parts off to the copper scrap yard. I tried to buy replacements from newark this month, they would have to be flown in from UK. Takes 5 weeks sometimes and a separate $9 box every time some back order comes in. I bought adapters from digikey, I got 1/4" stereo phone receptacles to 1/8" stereo phone plugs. Little problem of no description of sex and no picture. ^&#^*(! I still can't listen to my replacement repaired PV8 mixer on earphones. I can't stop in at Fry's, nearest one is Chicago 180 miles away.
What newark has today may vary. I bought 1/8 stereo phone recept to 1/4" stereo plug adapters from newark 18 months ago. the burglar carried them and all other parts off to the copper scrap yard. I tried to buy replacements from newark this month, they would have to be flown in from UK. Takes 5 weeks sometimes and a separate $9 box every time some back order comes in. I bought adapters from digikey, I got 1/4" stereo phone receptacles to 1/8" stereo phone plugs. Little problem of no description of sex and no picture. ^&#^*(! I still can't listen to my replacement repaired PV8 mixer on earphones. I can't stop in at Fry's, nearest one is Chicago 180 miles away.
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You want round ones?
Leds | Products Available at Jameco Electronics
And at least on the first item, the data sheet is included, you can download it.
Leds | Products Available at Jameco Electronics
And at least on the first item, the data sheet is included, you can download it.