Running a small DC solenoid

Discussion in 'The Projects Forum' started by Chuckiechan, Nov 8, 2010.

  1. Chuckiechan

    Thread Starter New Member

    Nov 5, 2010
    2
    0
    I have a small solenoid (Jameco 149762 - PN SMT-1632S12A):
    Specs:
    12 volts DC
    7 watts
    21 ohms coil resistance

    My power supply is:
    12 VDC (From an old printer or something)
    1.25 Amps

    I'm thinking I need to add a 15 W, 20 Ohm resistor to protect the solenoid.

    Am I on the right track here, or am I over thinking it.

    It's actually being used to push a doorbell acting as a switch for something else, so it won'[t be a continuous current unless someone the button gets jammed down.

    Thanks in advance...
     
  2. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,574
    230
    With a 12v supply, the 12v solenoid will draw only the current it needs...~0.6A. The 1.25A rating on the supply is just the maximum that it can supply.

    Ken
     
  3. Chuckiechan

    Thread Starter New Member

    Nov 5, 2010
    2
    0
    So I should just wire it directly and not use a resistor?

    Thanks for your help! :)
     
  4. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,574
    230
    With what you've described, there should be no need for a resistor.

    Ken
     
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