12v down to 6v

Discussion in 'General Electronics Chat' started by dannysamworth, Apr 20, 2013.

  1. dannysamworth

    Thread Starter New Member

    Apr 20, 2013
    2
    0
    Hi,

    I would like some help with the following that I am trying to do.

    On the bottom of my alarm siren are 2 blinking leds which run off 4 x 1.5 volt batteries ( C type )

    Due to modifications the batteries are gone and there is a 12v 1 amp dc supply to the siren, and this is what I want to run the led circuit from.

    I would be grateful for any help in making it possible to do the above.

    Danny
     
  2. z3ngew

    New Member

    Apr 18, 2013
    13
    0
    I'm sry, do you mean you want to reduce your supply voltage from 12vdc to 6vdc?
    if you want to do that, you can simply use a voltage divider circuit, or use voltage regulator ic.

    Good Luck,
    z3ngew
     
    Last edited: Apr 20, 2013
  3. paulktreg

    Distinguished Member

    Jun 2, 2008
    611
    120
    How much current do the LED's require, very little I presume?

    You could go down the path of using a voltage regulator but in this situation maybe something like 10 or so 1N4004 diodes is series would be easier.
     
  4. ScottWang

    Moderator

    Aug 23, 2012
    4,853
    767
    What you means is when the siren working and two LEDs is blinking, right?
    1. 12v 1 amp dc supply.
    2. How is the current of siren?
    3. How is the LED V/I(3V/20mA)?
    4. How do you control the siren?
    (Bjt, mosfet, relay)
     
  5. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    For 24 volts to 2 blinking LEDs, this could be as simple as a resistor and a zener diode, but we have to make sure. Need more information.
     
  6. paulktreg

    Distinguished Member

    Jun 2, 2008
    611
    120
    I presume this will be a commercially supplied alarm system? The external alarm siren box will have a permanent 12V supply that charges an inbuilt SLA battery with a 12V signal that inhibits the siren, cut the wire the alarm goes off.
     
  7. dannysamworth

    Thread Starter New Member

    Apr 20, 2013
    2
    0
    Thanks for all the replys. I'll try to provide some more information, I'm not very experienced with electronics.

    The 2 small led's just constantly blink from side by side just to alert of the alarm. They have no relevance of if the alarm is armed / disarmed.

    I will investigate and see if I can gather any details from anything on the circuit board.

    After a modification I carried out I needed to remove the battery compartment that supplied the power for these led's. 4 x c type batteries. ( these would usualy run the led's for 18 months +\- .

    There is a perminate 12v dc 1 amp supply to the alarm box which in some way or Another would like to join up to the live and neutral wires that did run to the batteries.

    Thanks
     
  8. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    Alkaline C batteries for 18 months calculates to less than a milliamp. Please measure the current that is being used from the batteries.
     
  9. killivolt

    Active Member

    Jan 10, 2010
    341
    310
    Installing a secondary supply, maybe a UPS. Then trigger that supply to run both the alarm and LED or Lights.

    I would think the LED's wouldn't be to bright.

    But, then again I don't know what you are doing with it, either.
     
  10. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    I'm thinking it's just a capacitor, a CMOS timer, and a couple of blinking LEDs. The low duty cycle keeps the average current to less than a milliamp and a resistor to a zener would do this job.
     
    Last edited: Apr 21, 2013
  11. killivolt

    Active Member

    Jan 10, 2010
    341
    310
    #12, I'm trying to understand if he's trying to re-charge the batteries?

     
  12. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    He's trying to remove the batteries.

    "the batteries are gone and there is a 12v 1 amp dc supply to the siren, and this is what I want to run the led circuit from"
     
    killivolt likes this.
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