1vdc to 12vdc to energize a relay

Discussion in 'The Projects Forum' started by Jaden Dick, Mar 30, 2015.

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  1. Jaden Dick

    Thread Starter New Member

    Mar 30, 2015
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    I'm wondering what I would need to get something that is 1.4vdc up to 12vdc to energize a coil in a relay and what type of relay. It would be really helpful is someone would draw what I would need to do and what model of transistor, relay and diode I would need

    Thanks in advance
     
  2. MCU88

    Member

    Mar 12, 2015
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    You could try an astable multivibrator feeding an inductor. The astable multivibrator using transistors will operate at 1.4 volts, but not so sure you'd get 12 at the output. I built an LED pen torch years back that used this schema turn one AA cell battery of 1.5 volts into about 4 volts to drive an white led.

    Your better bet would to be to use something a bit more intergrated, specific and modern, such as an DC to DC inverter. This would be an single chip, an inductor, a handful of other passive parts hanging off the chip and not much else.

    Easy greasy all the best with it...
     
  3. ronv

    AAC Fanatic!

    Nov 12, 2008
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    Could you use a transistor instead oa relay to switch your load? Or does it need to be isolated?
     
  4. MrChips

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    Oct 2, 2009
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    Are you saying that you have 1.4VDC control signal and would like to energize a 12VDC relay?

    You can do that with an NPN transistor such as 2N3904. But you will need a 12VDC supply.
    You would put a 1kΩ resistor from the signal to the base of the transistor.
    Emitter goes to ground. The relay goes between the 12VDC supply and the collector of the transistor.
    The diode is 1N4001-1N4007 series. Any one will do.

    [​IMG]
     
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  5. Jaden Dick

    Thread Starter New Member

    Mar 30, 2015
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    So
    sorry if this is a dumb question but why would I need a resistor on the 1.4 volt wire don't resistors make the voltage even lower?
     
  6. MrChips

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    The base-to-emitter junction of a transistor looks almost like a dead short to whatever is sourcing the 1.4VDC.
    The transistor only needs about 0.7V to turn on. You want to limit the amount of current drawn from the 1.4VDC source to protect it from being destroyed.

    With a 1.4V source, the 1kΩ value might be too high. You can reduce it to 220Ω.
     
  7. Denesius

    Member

    Feb 5, 2014
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    Do you have 12 volts available in your project? If not, there are off the shelf cheap integrated circuits that will kick 1.5 volts up to 12- you'll only need a few components to make it work. You can also buy cheap (ie- a buck or two) modules on ebay & such that will do the trick. Share some info about what you're doing & it'll be a lot easier to get you a circuit
     
  8. Jaden Dick

    Thread Starter New Member

    Mar 30, 2015
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    Yeah I have 12volts available im trying to get it so that my 1 volt constant power when turn signal is on will turn off a 12volt power aka daytime running lights so you will be able to see my turn signal flashing when in use and when not in use the daytime will will come back on
     
  9. MrChips

    Moderator

    Oct 2, 2009
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    The owners of All About Circuits have elected not to allow discussions of automotive electrical system modifications/enhancements due to safety concerns, the potential of legal ramifications and the possible circumvention of vehicle regulations at the state and federal level.

    This thread is against the AAC forum rules, Chapter 6, as seen here:

    This can be found in our Terms of Service (ToS)
    Please do not bother to reword the question. It will not fly under the radar.

    Here is a site that may provide you with some assistance: Electro Tech Online

    Good luck.
     
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