Looking for 3v relay module

Discussion in 'General Electronics Chat' started by truwebs, Apr 24, 2016.

  1. truwebs

    Thread Starter Member

    Apr 2, 2016
    54
    2
    Can anybody recommend where to purchase a 3v relay module? Do they even exist? There are plenty of 5v ad 12v modules on the market.

    These falsely advertised 3v relay is the only one I have been able to find. It appears the same one is being sold on Amazon.
    http://www.ebay.com/itm/331413255692?_trksid=p2057872.m2748.l2649&ssPageName=STRK:MEBIDX:IT

    Thanks to the AAC community and many hours trouble shooting, the following better describes the above module.

    Advertised relay PCB as 3v relay. While the relay on the board may trigger independently with only 3 volts, the circuitry of the board demands a higher voltage to trigger the relay. Relay PCB has a EL817 opto-coupler for the input signal, it requires a 5V drive voltage on the Input in order to drive the onboard transistor which controls the relay coil current. With only a 3v drive, there is insufficient current to drive the opto and transistor. The module that the relay is mounted to is falsely advertised as 3.0V because the components on the board need more than 3 volts. In order to drive this relay with a 3v signal device, voltage level shifting needs to take place between 3v device and relay PCB.

    Thanks to Ebay for getting me a full refund.

    Regards,
    TRU
     
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,687
    900
    To give you actual recommendations, we need to know what current rating and voltage you need for the output. Do you want a mechanical or solid state relay? Is the switched load AC or DC?

    However, if you use the parametric search functions at Mouser or DigiKey, you will find many relays and relay modules that operate at 3V DC and even lower.

    John
     
  3. truwebs

    Thread Starter Member

    Apr 2, 2016
    54
    2
    Would like.. mechanical (cheaper)

    - Work voltage: DC 3V/3.3V
    - Control 10A 250VAC, 10A 30VDC load

    TRu
     
  4. truwebs

    Thread Starter Member

    Apr 2, 2016
    54
    2
    have looked at those sites only to find relays and not the full pcb module.

    TRU
     
  5. #12

    Expert

    Nov 30, 2010
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  6. truwebs

    Thread Starter Member

    Apr 2, 2016
    54
    2
  7. #12

    Expert

    Nov 30, 2010
    16,278
    6,791
    I don't think you can buy a relay with circuit board attached from a normal parts seller.
     
  8. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,687
    900
    The pinouts are fairly standard, or at least you can probably find a relay with the same pinout as the one on your PCB. Just unsolder, replace, and resolder.

    That will give you a better result than not having anything.

    John
     
  9. aidayley

    New Member

    Jul 26, 2016
    29
    4
    I just got some three volt relays off ebay they work great here is the link
    http://www.ebay.com/itm/5Pcs-Mini-3...702905?hash=item41aff154b9:g:1nEAAOSwbsBXpVJY

    AIDayley
     
  10. truwebs

    Thread Starter Member

    Apr 2, 2016
    54
    2
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