| ??? 02/10/06 01:36 Modified: 02/10/06 01:42 Read: times |
#109663 - Will work! Responding to: ???'s previous message |
Prahlad said:
The Red LED Vf=1.6V thus it wont allow any incoming singal >1.6V to go to non inverting pin of comparator. 
Dear Prahlad, if output voltage of transformer is zero, then, proper calibration assumed, potential at inverting input is nearly identical to reference voltage. In this case a voltage of 5V / (20k + 5k1 + 5k1) x 5k1 = 0.84V is dropping across the LED and current through the LED will be less than 1nA, which is totally negligible. If output voltage of transformer is at positive maximum, on the other hand, then about 1.6V drops across the LED. At inverting input of comparator then a voltage of (5V - 1.6V) / (20k + 5k1) x 5k1 + 1.6V = 2.3V can be seen. So, as Abhishek already mentioned, the circuit will work. Kai |
| Topic | Author | Date |
| Zero cross detector led. [ Kai ] | 01/01/70 00:00 | |
| Yes, still required | 01/01/70 00:00 | |
| Please Elaborate | 01/01/70 00:00 | |
| Input signal. | 01/01/70 00:00 | |
| CMIVR | 01/01/70 00:00 | |
| Input smaller than reference. | 01/01/70 00:00 | |
| yes works | 01/01/70 00:00 | |
| Will work! | 01/01/70 00:00 | |
| Re: Will Work. | 01/01/70 00:00 | |
| are you aware | 01/01/70 00:00 | |
| Searched entire page. | 01/01/70 00:00 | |
| sorry, it seems to be gone | 01/01/70 00:00 | |
Re: LPCxxx App note. | 01/01/70 00:00 |