Sanding down 5mm leds & Blinking led Question.

If I sand down flat the dome of a 5mm led will it be just about as good as an inverted cone led for wide viewing angle? Not using a reflector, just attention getter.

Also, are all old school leds rated at 20ma? Or did they run at less? I want to hook up an old school blinking led in series to make some high-output leds blink too. Unless someone could sell me just one or two modern blinking leds.

I can't remember (it's been 15 years!!! since I've hooked that style up) God that makes me feel old even though I'm in my mid-twenties. I already feel old /ubbthreads/images/graemlins/frown.gif

TIA.

Sanding an LED flat will make it wide angle viewable. You may want to try different levels of sanding tho. I use a stiff emery board (dollar store). then I use 1200 grit hoppy paper, this gets it to a frosted look. Then use a US bill, new 20's work great. The bill will give it a really clear finish.
As far as the blinkies, not sure.
Jeff

Blinking LEDs that I'm aware of pass sub-mA levels of current during the "off" cycle, so that any LED(s) connected in series will emit a very dim glow during this period, rather than being all the way off.

I tried to find a blinking LED to verify this, but was not able to. /ubbthreads/images/graemlins/jpshakehead.gif

Hmm. I did this back in the day with the old school "dim" leds and it worked fine. Perhaps though controlling a high brightness led it would still light up though.

Craig: did the old school leds run on 20ma too or was it lower? I don't remember if 20ma is the standard, or if that is considered "high power" vs the old school???

Any other ideas other than building a big ol 555 timer to make them blink?

Update on the flashing LED thing...yes, the flashing LED does pass enough current in its "off" state to allow LEDs connected in series with it to glow.

IsaacHayes: Yes, flashing LEDs can be run from the same 20mA supply you might connect a standard LED to.
20mA is a standard LED drive current, and has been for at least the last twenty five years or so.

Ok great. So leds only grew in eff. and output, not drive level. I was thinking the old school ran at like 2ma. heh.

Any idea for a small flash controler? I guess I might have to do a 555 timer /ubbthreads/images/graemlins/frown.gif

Isaac, I have a flasher around here somewhere that uses 2 NPN's and a res and a cap. I'll let you know if I find it.
Jeff

WildRice, thanks, I did some searching, a simple flipflop type circuit would probably work like that. Do you know how to calculate what frequency to tune it to? TIA

awww, com'on Isaac, BREADBOARD IT. honestly, not sure. The circuit I have is more of a pulse flasher, mabyee 20-30% duty cycle.
Jeff