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SSR basics

Discussion in 'General Electronics Discussion' started by evokanevo, Jun 13, 2012.

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  1. evokanevo

    evokanevo

    3
    0
    Jun 13, 2012
    Hoping someone might take a minute to a double-check that the solid state relay I found (AQV101) on digikey meets the below requirements.

    This SSR must:

    -Work with a 3V control input signal that can supply at most 1mA. The documentation states that the SSR needs a 2.3V signal, but I'm not sure if that's a lower bound. The development board that I want to control the SSR outputs a 3V signal, at max 1mA.
    -The SSR must support a 500mA load at 12V (solenoid valve). I know the SSR is rated for 700mA, but I'm worried about an inrush of current when the circuit is made. Is this something I should worry about?

    *Note that I'm looking at the DC-input/DC-output version, AQV10 series*
    http://www.digikey.com/product-detail/en/AQV101/255-1546-5-ND/570684
    http://pewa.panasonic.com/assets/pcsd/catalog/aqv-dip-low-on-resistance-catalog.pdf

    Thanks,
    Ivan
     
  2. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    Read page 2 of the datasheet it clearly states that the LED (input side) wants a typical 2.3mA - 5mA current and likely will turn off at anything under 2.2mA

    Time for a transistor to boost your developer board output...
     
    Last edited: Jun 13, 2012
  3. GreenGiant

    GreenGiant

    842
    6
    Feb 9, 2012
    another thing to look at is what are you switching?

    SSR's have "off state leakage current" this one is rated at 1uA max, not a lot but for some applications it can cause problems
     
  4. evokanevo

    evokanevo

    3
    0
    Jun 13, 2012
    I mistakenly thought that section was for AC relays. Anyway, I'll add a transistor to increase the available current and hopefully it will work out.
    The load is a 12V normally-closed solenoid valve, which allows fluids to flow when voltage is applied.

    Thanks for the help.
     
  5. evokanevo

    evokanevo

    3
    0
    Jun 13, 2012
    Here is the schematic. Does this mean current flows freely from 6 to 4 through the diode and the transistor, which is in parallel, controls current flow in the opposite direction?

    I misinterpreted the diode and transistor to be a single unit/symbol - this is incorrect I assume?

    Thanks in advance.

    [​IMG]
     
  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,482
    2,830
    Jan 21, 2010
    The load current on these things looks pretty small. Are you sure it's enough?

    The diode is the integral body diode of the mosfet. This should be reverse biased in most cases
     
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