Hi!
I am building another static grass applicator. It calls for a 12 VDC 200ma wall wart power supply. I have many 12 VDC supplies, but they all have no load measurements of 14 to 20 VDC. I know these are unregulated supplies, but what is the maximum no load voltage I should consider using?
My concern is because the first one I built worked very well for a few days, but then got overheated and the negative ion generator was destroyed. I surmised that maybe it was because the no load VDC of the supply was closer to 19 VDC. I've read since that the negative ion generator I used from Goldmine ($5) was no longer available and that it wasn't hardy enough. I am now using the one from Oatley in Australia ($14) and it certainly appears very well made. However, I don't want to take a chance on destroying it as well.
So, repeating myself, what is the maximum no load voltage I should consider using? If I use say18VDC, will it drop down to the 12 VDC or will the high noload harm the generator before it drops downs? Is there a problem if I use a supply capable of 500ma instead of the 200 ma?
Does it harm the generator if the + and ground of the applicator touch briefly to cause the load 15KV spark snap and brilliant light?
Thank you so much, in advance, for any insight you can provide. Ken
Ken,
You and I both built exactly the same device using the same materials (electronic goldmine ION generator). Mine is still working fine and I have used it a lot. Perhaps you received a defective generator the first time. I purchased the recommended wall wart and haven't had any problems.
The 12V wall warts often read around 14V with no load, I would use ones that are near that range. In general, I have had poor luck with unregulated supplies and now use mostly regulated supplies where the voltage matters.
I have accidentally touched the screen to the pin (the zap will wake you up!!!), but haven't seemed to cause any damage to the device....I certainly wouldn't make this a habit (although I know some kids that might:-). You might also double check your wiring for any connections that have come loose etc...
These grass guns work very well and have made my scenery efforts much more realistic. Good luck with the repairs...
Guy
see stuff at: the Willoughby Line Site
Larger amp capacity, 500ma vs 200ma, will not hurt. In fact if the circuit REQUIRES 200ma then you want to use a power supply slightly higher than this anyway so it isn't running at 100% load.
For better voltage, consider a slightly more expensive regulated wall wart, these include a voltage regulator to maintaint he specified voltage over the load range rather then have it goe way up under light load and then droop down as the load increases.
Or put a 14V light bulb in parallel with the input of the ion generator as a power on indicator plus a load to get the voltage of the power supply down.
Modeling the Reading Railroad in the 1950's
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Hi Kenkal
I am in Australia and have built a few static grass applicators using the Oatley Electronics ion generator (I intend to sell them when I have built a few more). The negative ion generator that they are currently selling is the B2. It has a maximum voltage of 12V. Yes most 12V power supplies float around 14V. I personally use 9V supplies, that way they float under 12V. It doesn't affect the performance of the ion generator and it keeps the voltage below 12V.
P.S. the milli-amp rating is not important in this case as the ion generator only uses about 20 to 30 milli-amps, pretty much any supply will do (some people use a 9V radio battery). The important thing is to keep the voltage down.
I built mine from this video which is in 3 parts http://www.youtube.com/watch?v=EAEmcqc-yIc works like a charm and it uses 2 d cells for power, hope it helps Jim.