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integration of optocoupled relays — Parallax Forums

integration of optocoupled relays

TomOfPEITomOfPEI Posts: 5
edited 2009-04-14 14:28 in General Discussion
I'm looking for suitable hardware such as optocoupled relays that can be used to switch higher current devices, but seem to have problems with voltage dropping at the javelin output. Currently using LAA110 (Clare) 8 pin dip. Can anyone suggest a suitable device and/or circuit?

Comments

  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2009-04-14 14:28
    It looks the device requires a forward current of 7-50mA, for a 1.3V forward voltage.
    (5V-1.3V)/10mA = 370 ohm.

    JavPin o---[noparse][[/noparse]370ohm]
    |>|----GND
    or
    JavPin o---|<|
    [noparse][[/noparse]370ohm]----VDD

    should allow you to switch.
    At 10mA, a Javelin I/O pin should not have any voltage dropping.
    Note that each I/O pin can deliver 25mA, but per group of 8 pins
    (portA and portB) the total is limited to 50mA.
    And best to switch the I/O to GND so the pin sinks current
    rather than sources current.

    regards peter
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