relay help please

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Joined: Mon Dec 17, 2012 11:45 pm

relay help please

Post by sonics » Tue Dec 18, 2012 12:00 am

hello all .please help i have been asked to build a buzz wire (you have to move a ring across a wire maze with out the buzzer going off when it touches the wire) its for a school fete , i need the buzzer to go off for a second or two. it needs to be safe and run on a 12 volt battery ,
the thing is i do not know the type of relay to use . been looking on ebay but cannot find one
ps happy xmas to all

Simon (Webmaster)
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Location: Nottingham, UK

Re: relay help please

Post by Simon (Webmaster) » Sat Dec 22, 2012 10:23 am

Given your (now deleted) abusive posting I'm not too willing to help - people post here in their spare time, no-one is paid to do so.

If you want the buzzer to sound for a couple of seconds you'll need a timer circuit. You could use a 555 timer in monostable mode, this can control a transistor to drive the buzzer. If the buzzer you want to use needs a high current you could drive a relay from the transistor to switch the buzzer, but it probably isn't necessary. I assume the whole thing will run from batteries? Google 555 timer circuits - there is plenty of info around. Electronics Assistant (available from the 'downloads' menu at the top of the page) can help with the component calculations.
Simon Carter
Electronics 2000

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