zking786

Externet, please elaborate on your point. I'm a beginning Electricity and Magnetism student and don't understand what you mean by "saturation coefficient".

I know what you mean, charge must be relative to something. I'm refering to the ground as a reference point, or a human body . If I connect one end of the capacitor to a metallic object, the charge should flow from the plate within the capacitor to the object, right? So, theoretically, if I touch one end of the capacitor, will I get shocked? Will the method I described work to charge a metallic object/conductor? If not, what will?

Where would I find a DC Chopper? Does the chopper also alter the frequency, or does it just chop the voltage curve at certain points (based on the frequency). How does a DC Chopper work?

Thanks for all the answers YT2095! With regards #4, I'm trying to use the charge stored in the capacitor to charge a metallic object (like a rod or a plate). I doubt simply hooking one end of the capacitor to the object will charge it. How would you recommend charging it? In post#2, 5614 says it's possible. Also, why use a diode? The capacitor can't charge a standard AA battery, can it?

When I say 50-100uF, I mean different capacitors of varying capacitances. Also, I've been told that I need to use an inductor and a transistor to charge the capacitor. (http://www.ee.washington.edu/conselec/CE/kuhn/labs/camera/fl.htm). How would directly charging the capacitor using a AA battery yield a high enough voltage? Doesn't it need to be steped up using an inductor? Also, why am I able to charge a capacitor to 1.5V or -1.5V when I plug it directly into the 1.5V AA battery? If it's pole sensative, shouldn't it only work in one direction? How would I be able to charge a plate conductor? BTW, thanks for all the answers.

I've opened up several transformers and have just found coils and metal (I think Iron) rectangles. The voltage IN is transformed to a different OUT voltage based on the ratio of the number of turns on either end. I'm wondering how frequency is adapted? Does the transformation also alter the frequency? I'm speaking specifically of transformations between 120VAC and 240VAC. The frequencies are different between 120V and 240V appliances, so a simple voltage transformation probably wouldn't suffice? Can someone help in explaining how these frequencies are altered?

I'd be using a 12V 24AH battery (maybe 26AH), definitely lead-acid. I guess I'd need to convert the DC to AC using a rectification system -- this would be the hard part. Then I'd use a transformer to convert the AC to 240V. The transformer's easy, but how should I rectify the DC voltage efficiently? YT2095, can you better explain why there would be back EMF? Also. what's a twin T RC filter? Lastly, I'm trying to build the rectifying circuit from old electronic components. What do I need and where can I find them? I have quite a few transformers, so the AC part shouldn't be a problem.

So the Na+ and Cl- ions aren't oxidized or reduced? Also, in retrospect, the precipitate wasn't really blue. It was a white foam. Does this change anything?

How can I use a capacitor to charge a plate? When I plugged the capacitor to a source of EMF, 1.5V battery and later a 19.5V battery eliminator, it only charged to about 3V. When I removed it from a camera, though, I got a HUGE shock -- more than 3V. Any idea why it won't charge fully? Is this because of the poles? Why are capacitors pole sensitive? Aren't they essentially two parallel plates separated by a dielectric? Thanks for the help!

Sorry! For clarification: DC-AC inverter. But don't inverters typically work both ways?

How can I build an AC-DC inverter. It should convert 12V DC to 240V AC. I'm trying to build a backup power supply which can handle 2-5A of current drawn. Anyone know of a simple circuit which can handle 2-5A?

I've been experimenting with capacitors (50-100uF from camera circuits). I'm wondering how I can charge a capacitor. I can't just plug it into a source of EMF, I probably need to design or find some sort of circuit, right? What's the best way to charge metallic objects? I don't have a Van de Graaf machine and can't produce enough charge by induction by rubbing two materials. Can I use a capacitor to charge metallic objects?

Does anyone know what the mosquitoes senses are and how sensative they are? I've heard of contraptions that lure mosquitoes by their attraction to CO2. Why are they attracted to CO2? Does anyone know the hearing frequency range for mosquitoes? How do the antennae of a mosquito work?

I was trying to perform electrolysis using a smart charger and a battery eliminator in series (generating about 12V 1A). The EMF setup was connected to two aluminum electrodes which were submersed in brine solution. The intent of the exeriment was to obtain pure hyrdogen gas and a residue of an oxide of aluminum. I got something quite different... I found that the gases weren't flamable and thus couldn't be oxygen or hydrogen. A light-bluish/white precipitate was formed slowly at the surface. Over the course of the experiment, some of the solution must have mistakely spilled (due to my handling, since there wasn't any rapid bubbling). This water, when cleaned off the clear-coated table, left a faint blue residue on the otherwise dark wooden surface. Finally, the aluminum electrodes were barely worn (1 cm diameter was unchanged), and I ran the electrolysis for about an hour. The results have posed the following questions: 1. What could the gases that were produced be? 2. What could the precipitate formed be? 3. How can I remove the barely-noticable light blue stain from the table? Interestingly, it isn't some sort of crust on the surface, it seems like it has actually stained the clear coat. 4. What can I do differently to produce hydrogen? Why doesn't this apparatus produce hydrogen? Any help will be greatly appreciated. Thanks!

I guess the moment I dreaded is here... I guess I must learn about vector calculus to better understand electrostatics. I know first-year university-level Calculus and first-year mechanical physics. So, I have a basic understanding of vectors. Could you, introduce vectors to the equations in a simple way? Maybe with an explanation, along with the symbols. Once again, thanks for all your help. These concepts are actually starting to make sense!!!

There's no way you would reach the other end of earth when falling through one side. Due to large aerodynamical drag forces (especially in a tunnel!), you can't expect to get too far. I'm not sure how we would take terminal velocity into account, considering our rate of gravitational acceleration is decreasing. Thus, it may be around 9.81m/s/s at the surface of earth, but eventually reaches 0m/s/s at the core. You'd need to use differential calculus to compute a modified gravitational acceleration in motion equation. Then you could deduce whether you would or wouldn't reach terminal velocity. As others have accurately stated, eventually, you would oscillate within the core and ultimately reach the center.

To clarify my requests: 1. Firstly, what is flux? 2. Secondly, I've seen various equations that include (3 cos^2 (x) +1 )^.5 How does this fit in? 3. How does torque relate to this equation and Gauss' laws. 4. How were Gauss' laws derived. I don't want to simply memorize the equations, I'd prefer to understand how they are derived and what they signify. 5. Lastly, what is a Gaussian Surface? Thanks for your prompt assistance!

I have been trying to learn college-level electrostatics at home. I've understood charges, electric fields, and voltage, but haven't quite grasped Gauss' law and some of the capacitance theorems that base off of it. Every site I have gone to seems to explain Gauss' law in a tricky, vector-related form. Since I only have a basic understanding of vectors, I can't completely understand how the formulas and calculations work. Not to mention my confusion with the various symbols in the equations. Is there anyone who can simply explain the law and any necessary prerequisites to understanding it? Any help you can provide will be valuable in my pursuit of knowledge. Thanks!

I agree with DaveC426913, but don't see what you mean by it being a paradox is the objects are perfectly rigid. Since momentum is conserved in all situations, the train will, in any case, decrease an infinitesimally small amount.

No other takers

I should probably provide a little context for this question . I'm looking for ideas for a Caltech prompt, "Fill the box with something you think is interesting". Any ideas? I was thinking of a a math-related joke or a couple of interesting scientific experiments, but need some ideas.

Well, I've posted it in most of the science forums to try to gain riddles from the various domains of science. In this case, chemistry. Also, could you elaborate on unification of the fields.

What's the toughest science-related riddle you've come across? Post any humorous or difficult riddles here.

That makes sense, sublimation is a phase change directly to gas (from solid in this case). Question is, at high temperature will the carbon bond to the disassociated oxygen? I guess I might have to pass the gas through lime water to find out.

the tree: How did you derive that integral? Also, this might sound extremely elementary, but why don't you have an upper bound on the integral? Also, since r varies with time, how can you have it as one of the bounds. Important thing to consider is I only have one year of calculus (brief differential eqns unit). Would appreciate clarification.