| ??? 05/12/06 18:11 Read: times |
#116121 - He is right, the Vf max for the LEDs you Responding to: ???'s previous message |
Andy said:This way, you need a kind of 'H' bridge arrangement to reverse the current, with the possibility for the whole thing to be OFF.
He is right, the Vf max for the LEDs you use is 2V5 and thus (since you need a series resistor - a LED is a current device) there is no way to avoid the 'H' bridge if all you have is 5V. If you have e.g. 12V some 'miracle circuit' can be designed that is not a 'H' bridge, but why go there. Allegro semiconductor has excellent intergrated 'h' bridge chips. Erik |
| Topic | Author | Date |
| Interfacing a Bi-colour LED | 01/01/70 00:00 | |
| a link to the bi-color LED datasheet | 01/01/70 00:00 | |
| Datasheet!! | 01/01/70 00:00 | |
| LED info | 01/01/70 00:00 | |
| He is right, the Vf max for the LEDs you | 01/01/70 00:00 | |
| More info on H bridge? | 01/01/70 00:00 | |
| that is what a H bridge usually is used | 01/01/70 00:00 | |
| be careful, but roll-yer-own | 01/01/70 00:00 | |
| Why no use a DPDT 5VDC relay? | 01/01/70 00:00 | |
| LED go poof | 01/01/70 00:00 | |
| Port pin go POOF! | 01/01/70 00:00 | |
| ?` | 01/01/70 00:00 | |
| Two inverters | 01/01/70 00:00 | |
| darn | 01/01/70 00:00 | |
| YES! | 01/01/70 00:00 | |
| Third color possible? | 01/01/70 00:00 | |
| Very nice however | 01/01/70 00:00 | |
| Two NAND's? | 01/01/70 00:00 | |
| how many LEDs | 01/01/70 00:00 | |
| a slight problem | 01/01/70 00:00 | |
| dynamic refresh | 01/01/70 00:00 | |
sure, but | 01/01/70 00:00 |