| ??? 10/05/06 21:03 Read: times |
#125865 - POOF Responding to: ???'s previous message |
Rows (07)of the LED Moving Message Display is to be controlled by 74LS42 Decoder IC
I guess that the LEDs use a minimum of 5mA each (what use is a display you can not see) so, for 69 LEDs the row driver current will be 345 mA. I took a gander at the LS datasheet and the short circuit output current is 55mA, so maybe the chip will survive just get very hot, but he will have some very dull LEDs. Now, of course, the CD4094 can handle A WHOLE MILLIAMPERE so, they may not get quite as hot In addition, do not forget that the current when multiplexing like he suggest will be 8 times more. Well, maybe the project is just misnamed and should have been called a toaster oven. most likely outcome: poof Erik |
| Topic | Author | Date |
| Detail of LED Moving Message Display Code | 01/01/70 00:00 | |
| I have asked and asked | 01/01/70 00:00 | |
| well I give him 10/10 for persistance | 01/01/70 00:00 | |
| Why the new thread? | 01/01/70 00:00 | |
| he does not like the - scores | 01/01/70 00:00 | |
POOF | 01/01/70 00:00 |