| ??? 09/12/08 06:36 Read: times |
#158209 - forward voltage... and series resistance (sometimes)... Responding to: ???'s previous message |
Kai Klaas said:
The actual forward voltage drop of a LED depends on crystal mixture and current and can differ quite a lot from type to type and brand to brand. forward voltage... and series resistance (sometimes)... depend also on particular lot and position of chip within the wafer, when manufactured... and then on the operating temperature, too... but of course, these are miniscule changes, maybe tens of millivolts, and can be neglected when the LED is used as an indicator. They come into play when the LED is to be used in some "exotic" way, e.g. driven at the "edge" for some reason, multiple of them connected parallely (strongly discouraged), an array which is supposed to provided uniform light, in photometric applications... JW |
| Topic | Author | Date |
| voltage rating for Chip LEDs | 01/01/70 00:00 | |
| same, of course | 01/01/70 00:00 | |
| datasheets really are your friends | 01/01/70 00:00 | |
| Voltage | 01/01/70 00:00 | |
| Not so fast... | 01/01/70 00:00 | |
| forward voltage... and series resistance (sometimes)... | 01/01/70 00:00 | |
| nothing exotic | 01/01/70 00:00 | |
| Some numbers... | 01/01/70 00:00 | |
| the question, the answers | 01/01/70 00:00 | |
| Many don't know about datasheets at all | 01/01/70 00:00 | |
| Unfortunately, in real life ... | 01/01/70 00:00 | |
| thank you every one for your advice | 01/01/70 00:00 | |
| series 0805 | 01/01/70 00:00 | |
| 0805 = package size | 01/01/70 00:00 | |
| Select-On-Test | 01/01/70 00:00 | |
| yeah its better to buy a few and test them | 01/01/70 00:00 | |
| Test for what? | 01/01/70 00:00 | |
| RE: Test for what? | 01/01/70 00:00 | |
| Usually... | 01/01/70 00:00 | |
| all i can find are hobbyist suppliers. | 01/01/70 00:00 | |
| Try "real" parts sources ... | 01/01/70 00:00 | |
| No, no, digikey isn't that nice... | 01/01/70 00:00 | |
Digikey | 01/01/70 00:00 |