Common sizes are T-1 and T-1 3/4.

 

I have a digital caliper and it is 3mm across the "barrel" (radius x 2). I ordered some 3mms. Someone earlier had said to get 5mm so that's what I got. You see, I know nothing about LEDs, and didn't even know that they are sold by their dimensions and that I should've measured the bad one in the first place.
I could've looked it all up, but then I wouldn't have the honor of bothering you guys. Am just having fun learning a bit and (eventually) making the toy work again.

 

I have a digital caliper and it is 3mm across the "barrel" (radius x 2). I ordered some 3mms. Someone earlier had said to get 5mm so that's what I got. You see, I know nothing about LEDs, and didn't even know that they are sold by their dimensions and that I should've measured the bad one in the first place.
I could've looked it all up, but then I wouldn't have the honor of bothering you guys. Am just having fun learning a bit and (eventually) making the toy work again.

Go back and read post #6

 

I have a digital caliper and it is 3mm across the "barrel" (radius x 2). I ordered some 3mms. Someone earlier had said to get 5mm so that's what I got. You see, I know nothing about LEDs, and didn't even know that they are sold by their dimensions and that I should've measured the bad one in the first place.
I could've looked it all up, but then I wouldn't have the honor of bothering you guys. Am just having fun learning a bit and (eventually) making the toy work again.

There are SOME "standard LEDS",so just like lamps they have a style. T1, T1 3/4 etc. The first LEDS were RED and that's all we knew. They drop about 2.1V. So early LEDs were RED, drop about 2.1V and need about 20 mA.

Then came green, yellow and the infamous blue LED. With BLUE we get the LED TV. We then got white and RGB. We got high efficiency LEDS which might operate at 1-2 mA or less and the color changes the or forward voltage. As the supply voltage gets smaller, the series resistor has a big effect. If your concerned about intensity, then you have to match Vf.

LEDs are current driven, but don't be surprised to see 5V and 12 V LEDS. These have the resistor built-in. Just like diodes, they have a max reverse voltageand they can be pulsed a lot higher than their ratings.

LED's are now all over the map. In one optocoupler only 0.1 mA of current is needed.

 

djsfantasi said, "Go back and read post #6"

I see it's right there in black & white. My apologies to all. At that time, I think I was thinking that volts & amps were what needed to be matched.

KeepItSimpleStupid said, "There are SOME "standard LEDS",so just like lamps they have a style. T1, T1 3/4 etc. The first LEDS were RED and that's all we knew. They drop about 2.1V. So early LEDs were RED, drop about 2.1V and need about 20 mA.

Then came green, yellow and the infamous blue LED. With BLUE we get the LED TV. We then got white and RGB. We got high efficiency LEDS which might operate at 1-2 mA or less and the color changes the or forward voltage. As the supply voltage gets smaller, the series resistor has a big effect. If your concerned about intensity, then you have to match Vf.

LEDs are current driven, but don't be surprised to see 5V and 12 V LEDS. These have the resistor built-in. Just like diodes, they have a max reverse voltageand they can be pulsed a lot higher than their ratings.

LED's are now all over the map. In one optocoupler only 0.1 mA of current is needed"

Thanks to this post, I'm actually starting to get a better picture of how LEDs actually work.
I'll make a (hopefully) final post after I get & install the new LEDs.

 

All fixed with 3mm LED. The new one is only very slightly brighter than the others.
Thx again.

 

I have a question related to this somewhat.

I have a cheap solar garden lantern that imitates the flickering candle of a pagoda. Flickering solar garden devices are hard to come by, and when it actually works it looks cool. But since new, it wouldn't work consistently after the first evening it was turned on. This was symptomatic of its twin, and both are store-exchanged units - the originals did the same thing, but I don't want to take them back again.. I want to get them working right.

In disassembling one, I found poor solder points, fixed them, and it seems to be okay for now. But this other one wouldn't turn on period the last time I tried it, so I've got it torn apart on my bench. I've resoldered some spots, one where only a slim part of the 26 guage wire was actually soldered to the board, and another with two wires that was a bugger to do with my tremor. I've taped over the light sensor so it wouldn't interfere, checked continuity of circuits, and found voltage everywhere it should be as far as my analysis of what should do what on the simple, tiny board. I bench-charged the 900mAh mHy AA battery, which like most rechargeables doesn't quite make it to its rated 1.5 volts, but should work as others do in my yard at 1.3-1.4v. Finally I got down to where the board had 1.4+ voltage on one black wire headed up into the LED holder, with I can't recall the exact number - 0.8 or 0.08v? - coming back on the white wire, but it still wasn't coming on; so last night I cut open the translucent plastic "flame" the LED was pressed into.

One post readily popped out of the imbedded LED glass, so I presume it wasn't stable to begin with and was the source of the problem.. I have a 5mm LED replacement, but it doesn't respond to the button battery test at 1.5v. It does off a 3v one. So I presume that LED won't work. All the 5mm white LED's in the Newmark catalog are rated 3v. The existing LED is different anyway - it is 4.9mm in diameter alright, but the glass is only about 5mm long! Not the 10-12mm of most. I see no 1.5v short LED's offered in the catalog. My other two flickering solar garden lamps are larger and use two AA batteries, so a standard 5mm lamp would be the ticket for them, but they run all night easily. The only work I ever did was replace a solar panel on one with a higher quality one.

Where can I find a proper replacement LED I can Lexel back into the translucent plastic "flame"? It doesn't have to be short, as there is plenty of headroom inside the "flame" the LED fits into.