You may also use a solid state relay (DigiKey 425-1217-5-ND, for example). Such relays have zero-crossing detection, and some come with an integrated snubber circuit.
The so-call 'Hockey Puck' Solid State Relay really offter optimal packaging with an easy interface. The heat generated by operating a solid state device is dumped from an all metal back. You can mount it to a metal chassis or an additional heat sink. The front side has easy to insulate connections. The only thing really missing is a fuse setup. The low voltage side often has a built in LED to indicate activity. They now come rated as high as 40amps at 240VAC.
All that power can be controled from a BasicStamp oin.
So, it is a bit silly to waste time on discrete component setups. If you really want to switch 5 or more AMPS, don't get the kind that mount to printed circuit boards as the board has some difficulty with carrying that high a current load. While the relay would be fine, the board may burn up!
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
SCRs transmit in only one direction, so the output would be half-wave rectified. TRIACs transmit both directions and is likely what you want. In lighting applications, typically there is an additional control circuit which limits the turn on point to be a zero cross point of the AC line, this reduces EMF generation in the load line and reduces voltage spikes through the element which is the leading cause of filiment burn-out. The same holds true for non-lighting applications (EMF), but the control circuit is most prevelant in lighting applications.
William's suggestion of using an optocoupler on the trigger is very wise because it reduces the current sourced by the SX pin and also provides an additional layer of isolation from the AC mains.
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Post Edited (Paul Baker) : 12/13/2005 9:33:06 PM GMT
Lightfoot
Posts: 228
Comments
Use a TRIAC ( BT137 ) and a small optocoupled solid relay ( MOC3011 ).
That will do it.
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Greetings from Germany,
G
All that power can be controled from a BasicStamp oin.
So, it is a bit silly to waste time on discrete component setups. If you really want to switch 5 or more AMPS, don't get the kind that mount to printed circuit boards as the board has some difficulty with carrying that high a current load. While the relay would be fine, the board may burn up!
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
William's suggestion of using an optocoupler on the trigger is very wise because it reduces the current sourced by the SX pin and also provides an additional layer of isolation from the AC mains.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·1+1=10
Post Edited (Paul Baker) : 12/13/2005 9:33:06 PM GMT
I was confusing thyristors with the EL train control systems (I live in Chicago), thats DC, so it that case it would work.
Post Edited (Lightfoot) : 12/14/2005 5:47:54 AM GMT