I am attempting to make a static electricity generator for a mate to use to make model grass stand up.
So I built this voltage doubler thing with diodes and capacitors, and it works great when I plug it directly into the mains. Static electricty things happen, big fat spark off the end when I discharged it, and nothing blew up or caught fire.
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//paulmurray.files.wordpress.com/2016/02/static.jpg
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However, my mate is not willing to plug anything I build into the mains in his house, and I respect that. Even though it wasn’t me who nearly burned his house down last time we built something. It has to run off a battery.
So. To power this thing, I need some sort of oscillator. I got on wikipedia and found the description of a multivibrator, and that seems to be the go. A visit to Jaycar and a bag of assorted transistors and capacitors later, and I am having some success but I am not managing to make the damn thing oscillate. I managed to get a transistor turning an LED on and off. I hooked up some capacitors and got the led turning off when I touched the lead and then fading back into full brightness, which was cool. I hooked two transistors together in a pair and the thing was so sensitive if I touched one of the leads the led would switch.
But it won’t oscillate.
I’m working off this diagram here:
://upload.wikimedia.org/wikipedia/commons/thumb/6/6a/Transistor_Multivibrator.svg/220px-Transistor_Multivibrator.svg.png
Can’t for the life of me figure out what resistors r1 and r4 do. They go to the collector, so I’m guessing that they are the actual loads. I use some 220nF caps for c1 and c2, and 4.7M resistors for r2 and r3, which should make it blink slow enough that I can see what’s going on. I am not going to run out and get an oscilliscope at this stage.
My problems are:
Where do I stick the leads going into the voltage multiplier? Do I put them in in place of R1 and R2? Do I put them across a resistor and that gets put somewhere? (my other problem is polarity - I might need to grab the opposite transistors and reverse things - not really keen on the idea of desoldering all those diodes).
What are suitable values for the resistors? I’m suspecting that the reason I’m not seeing oscillation is that I’m using such a high resistance for r2/r3 that it won’t drive the transistors properly.
I’m not quite at the stage where I’m ready to lay out cash for an oscilliscope.
I can put my gear in a bucket and bring it to MHV or anywhere, I’d be happy for someone to fly over Curtin here and have a look.
Would someone be willing to have a look at this thing?