| ??? 11/26/10 01:10 Modified: 11/26/10 01:16 Read: times |
#179622 - Hhm, leakage currents? Responding to: ???'s previous message |
Dear Raghunathan,
your outputs seem to suffer from heavy leakage currents. So, offer these leakage currents a path to ground ARROUND the LEDs by paralleling a suited "shunt" resistor directly from each connector's pin to ground (24DG), like Erik already suggested. Also, increase the threshold of LEDs by inserting a zener in series to each LED. Example given, replace each 2k2 resistor by a series circuit of BZX85-C10 zener and 1k2 resistor. The "shunt" resistor is chosen properly, if the voltage drop stays well below 7.5V, when the connectors' pins are emitting low level. Are the outputs of your PCI card "open emitter"? This would explain the rather high leakage currents... Greetings from the snow-white Black Forest! Kai Klaas |
| Topic | Author | Date |
| Switch off a LED array | 01/01/70 00:00 | |
| What are the switches? | 01/01/70 00:00 | |
| Virtual ground at 3.3V | 01/01/70 00:00 | |
| 3.3V Regulator Idea | 01/01/70 00:00 | |
| The 3.3V regulator idea might not work! | 01/01/70 00:00 | |
| It is a SOURCE board ... | 01/01/70 00:00 | |
| Hhm, leakage currents? | 01/01/70 00:00 | |
| Solution in sight | 01/01/70 00:00 | |
| LED tester shows bad design/bad parts | 01/01/70 00:00 | |
| Who is the designer ?? Stand up.... | 01/01/70 00:00 | |
| LED tester shows bad design/bad parts | 01/01/70 00:00 | |
| I wouldn't rely on anything published by NI | 01/01/70 00:00 | |
| crying wolf again?? | 01/01/70 00:00 | |
| NI is not a fly-by-night-operator | 01/01/70 00:00 | |
| No question about that | 01/01/70 00:00 | |
| The "crying wolf" is right here... | 01/01/70 00:00 | |
| I also say it... | 01/01/70 00:00 | |
Leakage current analysis | 01/01/70 00:00 | |
| Also, the voltage across the load.... | 01/01/70 00:00 |