Relay

Discussion in 'The Projects Forum' started by aaad2, May 30, 2012.

  1. aaad2

    Thread Starter Member

    May 30, 2012
    50
    0
    Hi people,

    Im not so sure on what type of relay it is used in this circuit diagram:
    [​IMG]

    I have look on ebay but there are quite a few types of relays (dpdt) that are 12v

    thanks in advanced
     
  2. panic mode

    Senior Member

    Oct 10, 2011
    1,318
    304
    12VDC relays with 600 Ohm coils are common. The only thing we still don't know is voltage and current rating of the contacts. spec of the relay or device that is part of will reveal that.
     
    aaad2 likes this.
  3. aaad2

    Thread Starter Member

    May 30, 2012
    50
    0
    Im trying to build this circuit and currently I do not know what the relay should be. I have searched on ebay and found this:
    http://www.ebay.co.uk/itm/RS-12-12V-DC-Relay-DPDT-2PDT-1A-24VDC-125VAC-2-Circuits-/200703591330?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item2ebaddc3a2
     
  4. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    they are just showing a typical 600 ohm coil, DPDT relay, the contact ratings all depend on what you are connecting to them, if you are connecting a motor, it should have enough current capabilities to handle the motor current draw, if you are just using it as a contact closure type of device, then any low current relay contacts may be sufficient..... so to better answer your question, what are you planning on connecting to that circuit once you have built it?
     
    aaad2 likes this.
  5. BSomer

    Member

    Dec 28, 2011
    433
    106
    That will work for the circuit as long as the load you are switching is less than 1 amp @ 125 VAC or 2 amps @ 24 VDC. So the question is... What are you turning on/off with the circuit?
     
    aaad2 likes this.
  6. aaad2

    Thread Starter Member

    May 30, 2012
    50
    0
    I am just trying to build that circuit, the PIR sensor will allow the LED to switch on when movement is detected.
    It does not need to be connected to other things.

    this is the website:
    http://electroschematics.com/6039/security-light-switch-with-pir-sensor/
     
  7. aaad2

    Thread Starter Member

    May 30, 2012
    50
    0
    It is just the LED

    Because the PIR will detect movement and cause the LED to turn on

    this is the website:
    http://electroschematics.com/6039/security-light-switch-with-pir-sensor/
     
  8. aaad2

    Thread Starter Member

    May 30, 2012
    50
    0
    furthermore, the circuit shows a LED at the bottom right, that is what the replay will turn on. right?
     
  9. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    1 set of contacts turns on the LED the other can connect to something else, the relay you found on ebay should work just fine.
     
    aaad2 likes this.
  10. BSomer

    Member

    Dec 28, 2011
    433
    106
    I see that there is an LED connected to one of the relay contacts. The other set of contacts, labeld "SW OUT", on the relay is intended to be connected to something you want to control. That portion is the determining factor to the load capacity of the relay. If all you want to do is build the circuit just for the learning process, then the relay you found on ebay will work fine for you. The "code" you see in the listing is just a model # and some info about the relay being sold.
     
    aaad2 likes this.
  11. aaad2

    Thread Starter Member

    May 30, 2012
    50
    0
    would it be possible for me to connect a switch there? (in the 'sw out')

    I want to connect multiple Super bright LEDs(about 4-8 LEDS) [more like a spot light]

    how should i go ahead with that then? should I just add the LEDs on the circuit(where that single LED is) making it parallel or series?

    and once again thanks people for the help
     
  12. aaad2

    Thread Starter Member

    May 30, 2012
    50
    0
  13. BSomer

    Member

    Dec 28, 2011
    433
    106
    Yes, though I do not know why you need to as the relay is essentially a switch.

    It is fairly simple to do that. Just connect your power supply positive for the LEDs to the relay, one of the SW OUT pins, then connect your LEDs anode to the other relay contact labeled SW OUT. Connect as many LEDs in parallel or series, your choice but dependent upon the voltage supply you are using. Connect the cathode of the LEDs to your current limiting resistor(s) then to ground.
     
    aaad2 likes this.
  14. aaad2

    Thread Starter Member

    May 30, 2012
    50
    0
    So I just connect some LEDs at the 'SW out' section(two pins)? But how do I know which is the anode and which is the cathode?

    thanks
     
  15. BSomer

    Member

    Dec 28, 2011
    433
    106
    Here are some visual guides for you. :D
     
    aaad2 likes this.
  16. aaad2

    Thread Starter Member

    May 30, 2012
    50
    0
  17. BSomer

    Member

    Dec 28, 2011
    433
    106
    Yes that relay will work.

    The pins you have labeled 1 & 8 are the coil. It doesn't matter which is positive and negative as long as the protection diode goes in like on your first schematic. Pins 2, 3, & 4 are one set of relay contacts. Pins 5, 6, &7 are the second set of contacts.

    The schematic of the relay is just an easy to use representation of the internal components of the relay. It does not necessarily mean that is how the pins actually are.
     
    aaad2 likes this.
  18. aaad2

    Thread Starter Member

    May 30, 2012
    50
    0
    Now I am even more confused :confused:
    on the left diagram, the pins that are connected(the bottom set on contacts) are pins 2 and 3?(compared the right diagram)
     
  19. BSomer

    Member

    Dec 28, 2011
    433
    106
    Do not get hung up on the pin numbers. You will find that when you order the relay you need or if you look at a datasheet of a relay, the pin numbers are really different than what you think they are.

    Just look at the contacts as NO - C - NC, which is Normally Open - Common - Normally Closed. If you can identify them that way you will be in better shape.
     
    aaad2 likes this.
  20. aaad2

    Thread Starter Member

    May 30, 2012
    50
    0
    thanks for the help, I just hope that when I connect everything up, the relay doesn't blow or something like that :|
     
Loading...