Hi All
  Just to be safe I would snub the coil or put a diode acrooss it.
  TTYL
Wally


>From: Luis Moreira <Luis.Moreira@JET.EFDA.ORG>
>Reply-To: pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU>
>To: PICLIST@MITVMA.MIT.EDU
>Subject: Re: [EE]: Relay & Opto Coupler & Transistor
>Date: Sat, 10 Jan 2004 07:16:22 -0000
>
>Hi Rafael
>         We do it all the time depends on the currente and voltage
>required.
>as the voltage used is the same you just have to watch the max currente
>allowed in the opto-isolator.
>hope it helps
>         best regards
>                         Luis
>
>-----Original Message-----
>From: Rafael Vidal Aroca [mailto:rva@GRAD.ICMC.USP.BR]
>Sent: 09 January 2004 23:44
>To: PICLIST@mitvma.mit.edu
>Subject: [EE]: Relay & Opto Coupler & Transistor
>
>
>         Hi guys, there is a question i'm always in doubt. Let see if
>anyone
>can
>make it clearer.
>
>         I always followed the traditional rules as the diagram below taken
>from
>http://www.hut.fi/Misc/Electronics/circuits/parallel_output.html
>
>                                                    V+  (12V)
>                                                   |
>                                      +------------+
>                                      |            +------+
>Parallel                            |            |      |
>Port                                |    D1     ---     |
>                                      |   1N4001  / \    Relay coil
>            R1    1  ----------- 5    |          /---\    |
>   D(x) ----1k------| Opto-     |-----+            |      |
>                    | Isolator  |                  +------+
>   GND -------------|           |-+                |
>                  2  ----------- 4|                |
>                     CNY 17 or    |   R2        | /
>                     4N25         |   4.7K    B |/  C   T1
>                                  +--\/\/\/\/---|      BC547A or 2N2222A
>                                                |\  E
>                                                | V
>                                                  |
>                                            external circuit ground
>
>         But i already saw, and assembled myself a circuit without the
>transistor, with the 4N25 being connected directly to the relay and the
>diode. Is it right or wrong? What are the implications as both seem to
>work well.
>
>         Thanks.
>
>[]s Rafael.
>
>--
>http://www.piclist.com hint: The PICList is archived three different
>ways.  See http://www.piclist.com/#archives for details.
>
>--
>http://www.piclist.com#nomail Going offline? Don't AutoReply us!
>email listserv@mitvma.mit.edu with SET PICList DIGEST in the body

_________________________________________________________________
Rethink your business approach for the new year with the helpful tips here.
http://special.msn.com/bcentral/prep04.armx

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body