Pulsing a Solenoid

Discussion in 'General Electronics Chat' started by drbenne, Jan 13, 2015.

  1. drbenne

    Thread Starter Member

    Jul 30, 2013
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    0
    Hi guys,

    I'm working on pulsing a solenoid, not very fast, maybe at most 10 times a second. Right now the solenoid is a 12V continuous duty, 14 ohm coil, push type. I have a function generator to use for driving the signal but may implement a 555 timer later. I'm not sure which would be better for supplying the current to the solenoid, either a BJT or a MOSFET. The function generater can supply either TTL or CMOS level output.
    For now I plan on using just a 50% duty cycle but am also wondering how the amount of on/off time could affect how fast the solenoid can pulse due to factors such as the build up and collapse of the field around the coil. If anyone could make some suggestions I would appreciate it.

    Dave
     
  2. ronv

    AAC Fanatic!

    Nov 12, 2008
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    Your kind of at the place where it's a toss up. To saturate a BJT would take 100 ma. which might be a problem for your generator. The FET would need to be a logic level FET. Time probably makes no difference. If you want fast release time consider a zener diode instead of a plain old clamp diode.
     
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  3. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,551
    2,374
    Solenoids intended for high speed operation/repeatability are usually specially designed for such, as in dispensing applications.
    Have you experimented with it yet to see if it will perform at that speed?
    Whatever diode method you use it most likely will slow it down at some point.
    Max.
     
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  4. ronv

    AAC Fanatic!

    Nov 12, 2008
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  5. drbenne

    Thread Starter Member

    Jul 30, 2013
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    I pulled up the spec sheet for the generator and it only gave me a rating of 3Vpp for the ttl output, so I'm not sure on that. For the diode I was just looking at a regular 1N4001 but I'll take the zener into consideration.

    Unfortunately, this is the only solenoid that I have on hand. I'm sure if needed I can order something more specific for the application. I've done a quick test but the return spring is a bit too strong for the rated force of this solenoid, and I was just switching the power on and off of my power supply, so not a true test as of yet.

    Thanks, I have some FETs laying around at home, I'll have to see if any of those come close to this one.
     
  6. #12

    Expert

    Nov 30, 2010
    16,302
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    Here's a couple of .tuts on coil speed.
     
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