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TRIAC and Stamp Pin — Parallax Forums

TRIAC and Stamp Pin

Fast MiconFast Micon Posts: 16
edited 2004-10-11 11:37 in BASIC Stamp
How do I switch a 24-volt AC inductive load using a TRIAC and a Stamp pin?· The solenoid's inrush current is about 800mA and the sustain current is around 300mA.· I don't want to use a relay.· Could someone post a diagram and part numbers?

Thanks.

Comments

  • BSBob24BSBob24 Posts: 3
    edited 2004-10-06 23:33
    1. Buy a stamp PLC and rectifier

    2. Buy a 5-volt regulator (radio shack) and then use L.E.Ds to rectify (also radio shack)
    _________
    +24V≈ >----P1-| | __ |
    Gnd >
    P2-| +5v| (_) |
    /P3-|_Reg|____|
    \_____^^^---|>|-> Out +5v DC
    ()
    \-->Gnd
    ***Key*** |
    |
    ^^^ = Resistor |
    () = Capacitor |
    - / \ |= Wire |

    Resistor = 10K |
    Capacitor = |
    Small and Non-|
    electrolic |
    |
  • Fast MiconFast Micon Posts: 16
    edited 2004-10-07 21:39
    I believe this scheme will not work with the solenoid I have. The solenoid that must be switched on and off works only on AC and 24 volt. Rectifying the supply current will prevent it from opening and closing the valve it is attached to. I wanted to switch it on and off (24V AC) controlled by a Stamp pin with a buffer circuit. Maybe the correct place for this post is in The Sandbox (can the Moderator move this thread to The Sandbox?)

    Thanks,
  • CPUMANCPUMAN Posts: 55
    edited 2004-10-07 23:33
    Well I'd personaly just use solid state relays, it'd lower the number of components, though the only draw back would be it'd get expensive with a large project.· I couldn't tell you any part numbers but a couple of triac circuits I've seen are in a...

    Stamp Pin ---> Optical Isolator ---> Transisor ---> Triac

    configuration.

    Chris
  • OrionOrion Posts: 236
    edited 2004-10-08 00:46
    Here is a circuit I use to drive 24VAC underground sprinkler valves and relays.· It should have no problems driving your solenoid.·Just beware that the MOC3042 (optical isolator) will draw around 20ma on the input side.· You will want to drive it with a transistor or darlington array unless you have nothing else on that pin group.· This circuit will cost you under $3.00 much cheaper than SSR.

    Post Edited (Orion) : 10/8/2004 12:53:41 AM GMT
    bmp
    bmp
    triac.bmp
    385K
  • Fast MiconFast Micon Posts: 16
    edited 2004-10-08 04:01
    Thanks, that's exactly what I was looking for.· Let me just double check your schematic:· 24VAC IN goes on TRIAC's pin 1 (MT1) and 24 VAC OUT goes on pin 2 (MT2), which connects also to pin 4 on opto.· TRIAC's gate goes directly to pin 6 on opto, right?· From the schematic it seems that TRIAC has 4 leads.

    ·
  • OrionOrion Posts: 236
    edited 2004-10-08 20:01
    You have it right assuming you get the same parts.·· Make sure you have the resistor (680ohm) between pin 4 on the opto and the MT2 on the triac. Sorry my drawing is not that clear heres a fix. Heres the jameco part numbers MOC3042 = #113961, 2N6071A = #140425.
    bmp
    bmp
    triac.bmp
    385K
  • Fast MiconFast Micon Posts: 16
    edited 2004-10-09 02:09
    Thanks a lot for your help.· I have just ordered the parts.
  • basicstampedebasicstampede Posts: 214
    edited 2004-10-11 11:37
    Orion, (or anyone else)

    Have you ever (or do you know how) to use the Stamp with triac, at less than 100% level?

    That is, I want to do fire the triac at certain phase angle, like a light dimmer.

    Any idea?

    Thanks.
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