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basic stamp output to energize a relay? — Parallax Forums

basic stamp output to energize a relay?

erp1976erp1976 Posts: 3
edited 2008-02-18 14:44 in BASIC Stamp
Im using a BS2p and need to output to a relay (5v). Does anyone have suggestions on which one to use and do I need to worry about the emf created when I turn off the relay? Do I need to connect a diode to protect the stamp?

Comments

  • allanlane5allanlane5 Posts: 3,815
    edited 2008-02-18 14:41
    1. A BS2 can't put out enough current on an I/O pin to energize a relay. You'll need a 'driver', at LEAST a transistor circuit, and a Darlington Array (ULN2008) is in many ways simpler.

    2. Absolutely you'll need a reverse-biased diode across the coil to protect whatever 'driver' you use from the current surge generated when the magnetic field in the coil collapses when you turn it off.
  • David H.David H. Posts: 78
    edited 2008-02-18 14:44
    erp1976,
    I was searching www.Digikey.com, and they have a SIP reed relay of HE206-ND that might work for you. If the load is inductive, you may have trouble with EMF or inductive type kick, so a diode would be needed. They have a listing for one with a diode built in of HE207-ND but they don't have them in stock. You can also use an Solid State Relay, and the load will be isolated from the inputs. One part is the same package style is part number CLA274-ND. They have these in other pin out and styles, but this might get you started.

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    David


    There are 10 types of people in this world,...
    Those that understand binary numbers, and those that don't!!!
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