connecting a digital high/low signal to an external 9v circuit

joshuazvi

hi,

i would like to use an i/o pin from the basic stamp to turn on an alarm siren. the problem is it isnt strong enough to do it on its own. i have been having problems with relays. are there digital logic relays that can switch on other circuits? please help! thanks,

josh

Bruce Bates

Josh -

What you probably want is an SSR or solid state relay with a 5-6 volt "coil" and contacts appropriate for your alarm siren. If you need help sourcing them, just ask.

Regards,

Bruce Bates

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T Chap

also try a mosfet for switching, you could google up mosfet switching, they are easy to hook up and cheap.


here area few links

http://www.physics.udel.edu/~watson/scen103/mos3.html

http://www.physics.udel.edu/~watson/scen103/mos4.html

joshuazvi

bruce,

thanks for your advice. i actually am having a problem finding them. i must have scrolled through 100 relays on jameco. i have bought 3 relays in the past none of which worked, i'm afriad i just have no idea which relay i need.
thanks

josh

Bruce Bates

Josh -

Crydom makes almost any type of SSR you can imagine. Make your selection of type from there, and then go checking supplier web sites. Here is a link to the Crydom web site:
http://www.crydom.com/products/productFamilyList.aspx?idProductLine=3

Regards,

Bruce Bates

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Amaral

Have you consider switching the relay from the Vin using an npn transistor ?

Amaral.