| ??? 10/02/10 06:48 Modified: 10/02/10 07:10 Read: times |
#178854 - SSR? Responding to: ???'s previous message |
I second Stefan about considering CTR. You will have to be strict in getting PC817 C or D rank devices only. If you get for e.g. PC817A, you need 60mA to get 30mA at the output and then you exceed max. input current specs of 50mA. This is considering you have got 50% CTR part although specs go up to 600% max.
Also C or D rank devices may be expensive (and/or not available even, I couldn't find a PC817C / PC817D on digikey, farnell) than the combination of 'A' rank device coupled with a transistor. Just another suggestion: Think of Solid state relays like this? http://www.vishay.com/solid-state-relays/ Also look these darlington output optocouplers: http://www.fairchildsemi.com/sitesearch/fsc.jsp?command=eq&attr1=AAAFamily&attr2=Photo+Darlington+Output For PCB design study material, I think book by Bosshcart is good. |
| Topic | Author | Date |
| PC817 for isolation + driving relay? | 01/01/70 00:00 | |
| Why isolate relay coil? | 01/01/70 00:00 | |
| Re: | 01/01/70 00:00 | |
| Optos don't actually "isolate" from a EMC point-of-view... | 01/01/70 00:00 | |
| ......... | 01/01/70 00:00 | |
Star point grounding and filtering... | 01/01/70 00:00 | |
| PC817? | 01/01/70 00:00 | |
| Is LED current of 5mA is sufficient? | 01/01/70 00:00 | |
| no | 01/01/70 00:00 | |
| A darlington? | 01/01/70 00:00 | |
| SSR? | 01/01/70 00:00 | |
| RE: "book by Bosshcart " | 01/01/70 00:00 | |
| RE: "book by Bosshcart " - Link | 01/01/70 00:00 |