View Full Version : Relay Switch

08-31-2008, 07:28 AM
I need to switch on and off a standard 110 volt light bulb. I know this can be done with a relay switch. I will be using a BS2 to control the relay. Can anyone recommend a relay switch that works with the BS2? A name and model and or link to one would be great.



08-31-2008, 09:07 AM
Or use an SSR ...
You should read this article .. contains all you need including part no.'s

www.parallax.com/Portals/0/Downloads/docs/cols/nv/vol7/col/NV130.pdf (http://www.parallax.com/Portals/0/Downloads/docs/cols/nv/vol7/col/NV130.pdf)


'Necessity is the mother of invention'

Those who can, do.Those who can’t, teach.

09-02-2008, 09:48 AM
Try Radio Shack, if there is one close to you; they have various sizes of relays.· Some of them will fit a BS2 ckt. board.
Look at this: http://www.radioshack.com/search/index.jsp?kwCatId=&kw=relays&origkw=relays&sr=1 (http://www.radioshack.com/search/index.jsp?kwCatId=&kw=relays&origkw=relays&sr=1)


09-02-2008, 01:02 PM
For better or worse, the Shack has a relay that will work for you. Check out http://www.radioshack.com/product/index.jsp?productId=2062480&cp=&sr=1&origkw=relays&kw=relays&parentPage=search·it's a 5V unit and can switch 1 amp at 125 VAC, so you can easily control a 60-75 watt light, even up to a 100W. The relay coil·draws 90 mA, so you'll need a small transistor between your stamp and relay. While you're at the Shack, get a multipack of transistors for $2.59 http://www.radioshack.com/product/index.jsp?productId=2062586&cp=&sr=1&origkw=npn+transistor&kw=npn+transistor&parentPage=search·and· and another value pack of rectifier diodes for $2.79 http://www.radioshack.com/product/index.jsp?productId=2062589&cp=&sr=1&origkw=diodes&kw=diodes&parentPage=search
and some 330 ohm resistors. Simple diagram attached.

·"If you build it, they will come."

09-02-2008, 03:12 PM
Basically the choice is yours .. a transistor and relay or just an SSR as outlined.

My opinion is to use an SSR in such scenarios ...for a number of reasons -galvanic isolation,Zero Cross over,low switching current - no need for extra components.No need for protection diode (to protect against back emf generated by inductive load switching) and it is solid state (no moving parts) .

John Twomey

'Necessity is the mother of invention'

Those who can, do.Those who can’t, teach.