Today I run across these LEDs. When I got them, maybe 30++ years ago, they were in the boards of old equipment. And that is all I can remember.

There is not plastic focusing component as in the now older 5 mm ones.

The Vf is 1,5 V at 10 mA.

Detail: the cathode shows good continuity with the metallic body and terminals are definitely long.

What are they? Any special / specific application?

 

That looks like a hermetically sealed LED that's no longer hermetically sealed.

Hermetically sealed devices are intended for use in harsh environments.

 

Looks like the laser diode in the CD player I tried to fix.

 

Yes I thought that but they predate CDs for maybe two decades.

 

Yes I thought that but they predate CDs for maybe two decades.

HP Labs was making laser diodes in the late 70's, but they were quite large by today's standards; and power hungry.

 

My 40yo "antique" Red Diodes are identical to the 5mm one's today, except much much dimmer and the plastic shell dark red. Probably couldn't see em in bright sunlight. That one looks like it might have had a plastic "Lens" inserted into the metal base at one time. Since it is white they may have been different colors? Red, Yel, Grn??? Grasping at straws here...

 

My 40yo "antique" Red Diodes are identical to the 5mm one's today, except much much dimmer and the plastic shell dark red.

I've got most of a bag of 100 I bought from Jameco (will call no less) from circa 1977. Leaky things with mangled leads; kind of like they were rejects swept up from the floor. 10 cents each as I recall.

 

Yep, Jameco was my go-to back then. That is for what I couldn't buy locally from the guy who sold to all the local radio/TV repair shops. Bought a lot of chips and regulators from his shop before all the radio/TV guys went out of business and he moved into telephone installation and alarm systems supplies. The shop is still around now selling computer networking bulk cable, connectors, fiber, etc.

 

My 40yo "antique" Red Diodes are identical to the 5mm one's today, except much much dimmer and the plastic shell dark red. Probably couldn't see em in bright sunlight. That one looks like it might have had a plastic "Lens" inserted into the metal base at one time. Since it is white they may have been different colors? Red, Yel, Grn??? Grasping at straws here...

Sorry Sam. No, it is a dim red. Couldn't get the camera to catch the color right.

 

The three (or four) I got, have no traces of a previous plastic cover, at all.

 

it is a dim red

Wondered about that cause what I could remember was red only back then.

 

Yes the older LEDs back then were dimmer than the ones of today. In fact, by comparison they were very very very much dimmer. Todays high brightness multi-color LEDs really changed the LED world.

I think it is funny that one of the listed 'features' of the hermetically sealed LEDs is that they are hermetically sealed. Imagine the confusion if they didnt list that feature

 

Yes I remember "Hermetically Sealed" as one of the buzzwords of the 60s. Not exactly sure why, just a sign of the times...

 

Yes I remember "Hermetically Sealed" as one of the buzzwords of the 60s. Not exactly sure why, just a sign of the times...

That was the reason Herman was able to keep his job.

 

how hard and expensive is it to make a LED at home, that works good enough to be a real LED (be noticeable ) ? I never tried make a cat's whisker diode

 

how hard and expensive is it to make a LED at home, that works good enough to be a real LED (be noticeable ) ?

That's generally beyond the realm of DIY. It requires a lot of expensive equipment and working with dangerous chemicals.

 

It's amazing what you can make at home but it is not likely to be as good as a ready made device.

The cat's whisker diode is really easy to make just use some rusty steel and a sewing needle.

 

There have been many creative ways of making rudimentary diodes using things like a rusty razor blade and a pin or a nail (look up foxhole radio) but I don't think I ever heard of a DIY LED? I was thinking I had but can't find any reference to it. Of course the very first LED was a DIY... And the early commercial LEDs didn't put out very much light.

 

You can even make your own superconductor material if you feel like going through the process. Not me though.