Dark Activated Circuit

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Dark Activated Circuit

Postby noien » Tue Apr 19, 2011 11:20 pm

I wan to built this circuit below, using Songle SPDT Relay SRD 12V .(http://www.cytron.com.my/viewProduct.ph ... O0nVj8GtY=)
http://pcbheaven.com/circuitpages/image ... 012151.jpg

Though I connected as the same with the circuit above, the relay is not working
How should i connect it?
I try to connect the 3 pin side, the top and bottom pin to the diode, it is not working either
I try to connect the 2 pin side, the top and bottom pin to the diode, it is not working either

how do i connect the relay to the diode?
Thank you
noien
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Re: Dark Activated Circuit

Postby sich » Wed Apr 20, 2011 10:54 am

noien WROTE:I try to connect the 3 pin side, the top and bottom pin to the diode, it is not working either

These are correct pins. Please look at the image below.

relay.png

Are you using pnp transistors? Wrong connection at the transistor pins (this is a common mistake)?
Please check the voltage reading at LDR pin and both transistors' base(B). The signal level must be able to high enough to turn on or low enough to turn off the transistors.
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Re: Dark Activated Circuit

Postby noien » Wed Apr 20, 2011 11:03 am

Thanx for the reply.
I will try it later. The transistor is npn
1st is amplify then 2nd is switch
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Re: Dark Activated Circuit

Postby ober » Wed Apr 20, 2011 9:40 pm

Try the straight forward method.

Take the supply of 12V, there are two terminal right? Try connect 2 of 3 terminal on left side. Two of those terminal normally is top and bottom is the coil terminal, that is exactly like sich pointed out. So left 3 terminals which are the NO, NC and Com. Use multimeter, continuity check. Com will shorted to NC when the relay is not activated; while Com is shorted to NO when relay is activated. So you get all 5 terminal.

Agreed with sich on the transistor, you might need to change to PNP instead of NPN.
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Re: Dark Activated Circuit

Postby noien » Thu Apr 21, 2011 11:10 pm

erm, do I need to change both to PNP or just change the 2n2222 to PNP
thanx
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Re: Dark Activated Circuit

Postby yonghui » Fri Apr 22, 2011 1:27 pm

hi,

both pnp and npn transistor can be used, but connection will be different.
for that particular circuit connection, then u will need to follow accordingly, else u will need to reconfigure the circuit connection.


regards,
yh
thanks&regards,
yh
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