| ??? 08/22/05 03:38 Read: times |
#99790 - something is wrong... Responding to: ???'s previous message |
You really mean 0.12A? 120mA driving a LED will burn it... or, at least, will affect its useful life. Redo your testings using resistors and a current of 20mA or 30mA (it's the maximum current in usual LEDs). for short periods (miliseconds) of time I've read that is common using higher currents, but since you want an outdoor display I assume that some points may be lighted for many seconds at a time. the luminous values (2700 and 4500) are in what unit? milicandelas (mcd)? for a red I've been informed that the max is around 8500 mcd. for bluen and green I've seen specs of 15000mcd and over it. try this site: http://www.besthongkong.com they have LEDs with a very reasonable price and the specs seems honest (I don't have a luximeter so I have to believe on the vendors spec...) |
| Topic | Author | Date |
| Questionn - Not even brightness for LEDs | 01/01/70 00:00 | |
| Sounds like you've answered the question | 01/01/70 00:00 | |
| What minizium change I need | 01/01/70 00:00 | |
| Test some things | 01/01/70 00:00 | |
| Test | 01/01/70 00:00 | |
| Try PNP instead of NPN | 01/01/70 00:00 | |
| Both method | 01/01/70 00:00 | |
| Increase the voltage accross the load | 01/01/70 00:00 | |
| even brightness... | 01/01/70 00:00 | |
| Spec for LED | 01/01/70 00:00 | |
| something is wrong... | 01/01/70 00:00 | |
| RGB LED's Luminous | 01/01/70 00:00 | |
| even considering voltage will get you in | 01/01/70 00:00 | |
| Explain more | 01/01/70 00:00 | |
| simple, drop the multiplexing | 01/01/70 00:00 | |
| Will this work | 01/01/70 00:00 | |
| Erik says | 01/01/70 00:00 | |
| this will | 01/01/70 00:00 | |
| Can I use UDN2891a | 01/01/70 00:00 | |
| can't say | 01/01/70 00:00 | |
| probably means 2981 | 01/01/70 00:00 | |
if so, you just don't get it do you | 01/01/70 00:00 | |
| why would you do that ? | 01/01/70 00:00 |