| ??? 01/27/06 08:11 Read: times |
#108479 - Triac magic Responding to: ???'s previous message |
Triacs, like most other electronic items don't quite work as you might hope. As a few of us have mentioned, there are a few traps for the unwary:- 1/ holding current - a triac requires a minimum current to stay on once its triggered. Larger devices have larger holding currents. 2/ dV/dt. Due to the structure of a triac, a rapid change of voltage across it can falsely trigger it. The snubber circuit is to preclude this. 3/ Maximum current - what a triac 'sees' in real life can exceed what you might think is the maximum current. Therefore they tend to fail if not specified correctly. 4/ Maximum voltage - again, what the triac sees in real life can exceed what we may expect. Snubbers help with this also. There's a few more - especially when controlling an inductive load. At a guess, a BTA41 being a 40A device, would likely need a 100W lamp as a load. If the load is insufficient, it may blink and flash. The manufacturers give us a heap of specs for good reason - it pays to understand each of them! |
| Topic | Author | Date |
| MOC3021 | 01/01/70 00:00 | |
| Triacs only turn off at zero | 01/01/70 00:00 | |
| Motor, bulb | 01/01/70 00:00 | |
| More.... | 01/01/70 00:00 | |
| dI/dt | 01/01/70 00:00 | |
... or was it dV/dt ? | 01/01/70 00:00 | |
| Triac | 01/01/70 00:00 | |
| Domestic light dimmers use triacs | 01/01/70 00:00 | |
| Clarification required! | 01/01/70 00:00 | |
| Triac current and voltage | 01/01/70 00:00 | |
| the link linked to is dead | 01/01/70 00:00 | |
| Triac magic | 01/01/70 00:00 | |
| T shirt | 01/01/70 00:00 | |
| Well. | 01/01/70 00:00 | |
| Inductive loads | 01/01/70 00:00 |