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Best wall power supply for automotive 12v 1w ioniser module

Discussion in 'Power Electronics' started by Voltaic, May 11, 2015.

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  1. Voltaic

    Voltaic

    82
    1
    May 6, 2015
    • Power requirements: DC 12V
    • Power use: <1W

    So if I need a 12v power supply with .083 amps.

    But I only have a plug pack that supplies 150mA, would I need a resistor? Since with plug packs the voltage starts off higher than 12v but goes down under load.

    It is designed to be used in a car with a car's power supply system. I'm not sure if that is a constant 12v or it goes up or not?

    It's an ioniser module so it probably has delicate circuitry in there.
     
  2. Kiwi

    Kiwi

    348
    85
    Jan 28, 2013
    The voltage in a car is a nominal 12volts, but varies quite a lot during normal operation.
    Voltage can drop to 10v, or less, during cranking and then up to around 14v when the engine is running.
    Automotive accessories are made to take these varying voltages without failing.

    The ioniser will only take the 83mA current it needs to operate. A 12v 150mA plug pack should be fine to run it. Plug pack will only be running at about 55% load.
     
  3. Voltaic

    Voltaic

    82
    1
    May 6, 2015
    Ok thanks It's just that I have no way to actually test it, so if it was broken by too high a voltage I probably wouldn't know (apart from counting the dust particles in my projector beam). One of the higher current plug packs I tested started at 17.something volts.

    In an electronics book I am reading they mentioned a simple voltage air detector using two pieces of tin foil inside a jar connected to wires poking out (so when there was a charge on both leads the tin foil pieces would separate), do you think this would be an effective tester for negative ions in the air?
     
  4. hevans1944

    hevans1944 Hop - AC8NS

    4,580
    2,142
    Jun 21, 2012
    No. It has no way to distinguish positive ions from negative ions. The device you (almost) described is a (gold)-leaf electroscope. The two leaves are a single strip of thin foil folded in half and supported in the middle by a single "L" shaped wire exiting a glass jar (for visibility and to shield from air currents) through an insulating stopper. Any charge, positive or negative, collected on the wire will cause the leaves to repel.
     
    Last edited: May 13, 2015
  5. Voltaic

    Voltaic

    82
    1
    May 6, 2015
    So they will detect ions vs no or low ions.
     
  6. hevans1944

    hevans1944 Hop - AC8NS

    4,580
    2,142
    Jun 21, 2012
    Theoretically. It depends on the density of ions in the air, the size and weight of the leafs. There are better (more modern) ways to do this. The leafs could also be charged first, like with an electrophorus, and then ions of the proper polarity will discharge the electroscope.
     
  7. Voltaic

    Voltaic

    82
    1
    May 6, 2015
    The plug pack power supply I have is 150ma (meant to be 12v) but it's producing 19v.

    The ioniser is 12v with maximum of about 80ma current draw (I think).

    Would the 19v be too high for a device meant for use in a car?
     
    Last edited: May 14, 2015
  8. Kiwi

    Kiwi

    348
    85
    Jan 28, 2013
    Is that 19v measured with no load?

    I would guess that the voltage will drop when under load.
    Put a load on it and check voltage.
     
  9. Voltaic

    Voltaic

    82
    1
    May 6, 2015
    Yes it was with no load with the 12v supply test.

    I just tested it under load it was drawing about 20ma and the voltage was 12.2 with the 9v plug pack and you can feel the ionic wind on your tongue lol.

    It uses 2x carbon fibre wires cut at the end to form brushes. I assume one is the emitter and one is the collector, would they be better further apart or closer together to ionise more air?
     
    Last edited: May 14, 2015
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