Reducing 12vdc to 6vdc on a I C board

Discussion in 'Electronic Basics' started by cfpikelll@msn.com, Jul 1, 2006.

  1. Guest

    I'm not the brightest bulb around when it comes to building electronic
    circuits... I have ordered a 4 station remote 12vdc and it has a SPDT
    relay in the circuit. I want to use that relay to close a DPDT 15 amp
    relay on a seperate circuit board, but the coils on the DPDT relays are
    6 vdc. I don't know how to reduce the voltage from 12vdc. The power
    drain would be only the coils of relays. I have eight relays, but will
    not energize more than 2 relay coils at one time. Any info would be
    appreciated..... Charlie
    , Jul 1, 2006
    #1
    1. Advertising

  2. Si Ballenger Guest

    On 1 Jul 2006 14:49:04 -0700, wrote:

    > I'm not the brightest bulb around when it comes to building electronic
    >circuits... I have ordered a 4 station remote 12vdc and it has a SPDT
    >relay in the circuit. I want to use that relay to close a DPDT 15 amp
    >relay on a seperate circuit board, but the coils on the DPDT relays are
    >6 vdc. I don't know how to reduce the voltage from 12vdc. The power
    >drain would be only the coils of relays. I have eight relays, but will
    >not energize more than 2 relay coils at one time. Any info would be
    >appreciated..... Charlie


    You can put a common signal diode on the ground of a 5v voltage
    regulator to up its output to 5.7v, which might be close enough
    for the relay operation.
    Si Ballenger, Jul 1, 2006
    #2
    1. Advertising

  3. John Fields Guest

    On 1 Jul 2006 14:49:04 -0700, wrote:

    > I'm not the brightest bulb around when it comes to building electronic
    >circuits... I have ordered a 4 station remote 12vdc and it has a SPDT
    >relay in the circuit. I want to use that relay to close a DPDT 15 amp
    >relay on a seperate circuit board, but the coils on the DPDT relays are
    >6 vdc. I don't know how to reduce the voltage from 12vdc. The power
    >drain would be only the coils of relays. I have eight relays, but will
    >not energize more than 2 relay coils at one time. Any info would be
    >appreciated..... Charlie


    ---
    With all due respect to your admitted lack of brilliance, your
    description of what you want to do is very confusing.

    You say you've ordered a 4 station remote, whatever that means, and
    that it has a SPST relay in the circuit. What circuit? And only
    one? What about the other three stations?

    And then you say you want to use that/those relays to control some
    other relays with 6 volt DC coils, while stating that you'll have
    12V coming from the relays that'll be doing the controlling.

    Then you state that the driven relay field will be eight relays wide
    and, ostensibly, that that field will be driven by the 4 station
    remote and that either one or two 6V relays might be driven at the
    same time.

    Unless you can come up with a better description of your system I'm
    not interested in helping you.


    --
    John Fields
    Professional Circuit Designer
    John Fields, Jul 1, 2006
    #3
  4. Chris Guest

    wrote:
    > I'm not the brightest bulb around when it comes to building electronic
    > circuits... I have ordered a 4 station remote 12vdc and it has a SPDT
    > relay in the circuit. I want to use that relay to close a DPDT 15 amp
    > relay on a seperate circuit board, but the coils on the DPDT relays are
    > 6 vdc. I don't know how to reduce the voltage from 12vdc. The power
    > drain would be only the coils of relays. I have eight relays, but will
    > not energize more than 2 relay coils at one time. Any info would be
    > appreciated..... Charlie


    Hi, Charlie. Just find out or measure the resistance R of the 6V coil,
    and put an equivalent resistance in series with each coil. Half the
    voltage will be across the coil, half across the resistor.

    Be sure the series resistors are sized to handle the power. Wattage
    will be (6V)^2 / R, or 36/R watts.

    Good luck
    Chris
    Chris, Jul 2, 2006
    #4
  5. On Sat, 01 Jul 2006 14:49:04 -0700, cfpikelll wrote:

    > I'm not the brightest bulb around when it comes to building electronic
    > circuits... I have ordered a 4 station remote 12vdc and it has a SPDT
    > relay in the circuit. I want to use that relay to close a DPDT 15 amp
    > relay on a seperate circuit board, but the coils on the DPDT relays are
    > 6 vdc. I don't know how to reduce the voltage from 12vdc. The power
    > drain would be only the coils of relays. I have eight relays, but will
    > not energize more than 2 relay coils at one time. Any info would be
    > appreciated..... Charlie


    To run a 6 VDC relay coil from a 12VDC supply, you can use a series
    resistor with a resistance equal to the coil resistance and a power
    rating greater than the power spec of the coil.

    For example, here's a page that has a relay with a 6VDC coil with a
    DC resistance of 40 ohms, for an operating current of 150 mA:
    http://rocky.digikey.com/WebLib/Omron Web Data/LY.pdf

    And, the power is 6 * .15, which I'm too lazy to do the arighmetic;
    that's the power rating of the 39-ohm (standard value) resistor you'd
    use in series with this particular relay coil to run it off of 12V -
    to do yours, you'll have to look up the coil resistance or operating
    current, and do the arithmetic for your particular case - in either
    case, the resistor you want to use to halve the voltage will be equal
    to the coil resistance - look up "ohm's law" and "voltage divider". :)

    Good Luck!
    Rich
    Bobo The Chimp, Jul 2, 2006
    #5
  6. jasen Guest

    On 2006-07-01, <> wrote:
    > I'm not the brightest bulb around when it comes to building electronic
    > circuits... I have ordered a 4 station remote 12vdc and it has a SPDT
    > relay in the circuit. I want to use that relay to close a DPDT 15 amp
    > relay on a seperate circuit board, but the coils on the DPDT relays are
    > 6 vdc. I don't know how to reduce the voltage from 12vdc. The power
    > drain would be only the coils of relays. I have eight relays, but will
    > not energize more than 2 relay coils at one time. Any info would be
    > appreciated..... Charlie



    if you're always wanting to operate the same two relays at onece you could
    connect them in series, otherwise get some resistors of similar resistance to
    the relay coils (10% accuracy is sufficient) and rated for enough watts and
    connect the resistor in series with the relay coil.

    the paired resistor-relay will operate fine of 12V

    --

    Bye.
    Jasen
    jasen, Jul 2, 2006
    #6
  7. ehsjr Guest

    wrote:
    > I'm not the brightest bulb around when it comes to building electronic
    > circuits... I have ordered a 4 station remote 12vdc and it has a SPDT
    > relay in the circuit. I want to use that relay to close a DPDT 15 amp
    > relay on a seperate circuit board, but the coils on the DPDT relays are
    > 6 vdc. I don't know how to reduce the voltage from 12vdc. The power
    > drain would be only the coils of relays. I have eight relays, but will
    > not energize more than 2 relay coils at one time. Any info would be
    > appreciated..... Charlie
    >


    Hi Charlie, Here is a "picture" - view in fixed font.
    It uses an LM7805 voltage regulator, two 1N4001 diodes,
    and two capacitors - a .1 uF and a .22 uF.


    -------
    | o |
    |_______|
    /_______/|
    |LM7805 ||
    | ||
    |_______|/
    | | |
    +12 ---+-----+ | +---+-----+----> To relays (+)
    | | | |
    --- - --- -
    |.22| |D| | .1| |=|
    | uF| |i| | uF| |e|
    --- |o| --- |d|
    | |d| | |o|
    | |e| | |i|
    | |=| | |D|
    | - | -
    | | | |
    Gnd ---+--------+------+-----+----> To relays (-)

    Note the banded end of the diodes indicated by an
    = at the end of each diode. It is important that
    the diodes be installed that way.

    The circuit will provide about 5.7 volts, and your
    6 volt relays will work just fine on that.

    Mount the LM7805 on a small heatsink. The "package"
    style drawn is a TO-220 - make sure you get that
    style package for the 7805 and that the heatsink
    matches.

    The parts are available from Allelectronics:
    http://www.allelectronics.com/
    CAT #7805 1 for $.50 Voltage Regulator
    CAT 1N4001 15 for $.99 Diode
    CAT# RMC-104 1 for $.17 .1 uF capacitor
    CAT# RMF-224 5 for $1.00 .22uf capacitor
    CAT# HS-134 4 for $1.00 TO-220 Heatsink
    If you buy from them, do yourself a favor and get
    CAT# 1N4148 15 for $1.00. Take one of these
    diodes for each relay and install it across the
    coil of the relay with the banded end on the (+)
    side of the coil and the other end on the (-) side.
    Those relays may already have a diode installed
    across their coils - if so, the 1N4148 diodes are
    not needed.

    Ed
    ehsjr, Jul 2, 2006
    #7
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Ron G

    Reducing Car 12VDC to 10VDC, I need help

    Ron G, May 14, 2005, in forum: Electronic Design
    Replies:
    14
    Views:
    1,204
    Paul Burke
    May 16, 2005
  2. randomname

    how to increase 6vdc to 12vdc

    randomname, Sep 7, 2006, in forum: Electronic Basics
    Replies:
    7
    Views:
    610
    Roger Dewhurst
    Sep 12, 2006
  3. Jeff Dieterle

    6vdc from 12vdc supply

    Jeff Dieterle, Jan 1, 2007, in forum: Electronic Basics
    Replies:
    3
    Views:
    487
    Jeff Dieterle
    Jan 2, 2007
  4. VirtualMonitoring

    How to step down 12vDC to 6vDC

    VirtualMonitoring, May 27, 2010, in forum: Electronic Projects
    Replies:
    16
    Views:
    3,236
    Resqueline
    May 27, 2010
  5. skeer

    Stepping down 12vdc to 6vdc, max 1amp

    skeer, Apr 12, 2013, in forum: Electronic Projects
    Replies:
    4
    Views:
    446
    skeer
    Apr 13, 2013
Loading...

Share This Page