It would be responsible at this point to at least one important point:
50 volts DC --OR-- 36 volts AC are considered LETHAL by some standards under the exact correct conditions. Be careful with anything near those levels.
With a 6 volt battery and wires, you're fine, but you could always hook up an ignition coil from an old car and create 10,000 volts too. So we could easily leave experimenting with high voltage alone for now (good idea) and I'll just give you a quick history on why AC and higher voltages are common and DC and lower voltages are common associations.
DC is most often found with batteries. A battery creates a voltage from a chemical reaction. This reaction only creates so much voltage, usually something like 1.5 volts. If you look at an really old car battery you can see the filling caps for each cell. Each cell only makes so much voltage, so many are placed in series to get the desired final voltage.
AC is typically everything else, even though Edison orginally didn't want this. The reason Telsa's AC won over Edison's DC for powering our homes has an easy answer to it, and it has little to do with the electricity inside the home. Note we talk about 60 watt light bulbs, or 900 watt microwave ovens, and so on. A watt is a measurement of work performed, and a watt can come from DC the same as AC.
So why does a light bulb, commonly remembered as Edison's invention by even school kids, powered by AC coming from Telsa partnered with Westinghouse near the turn of the century? Economics. Using AC allowed for economies of scale and lower prices that left DC behind.
AC allows for a transformer to change voltage/current. The transformer is like a car transmission, in first gear you have lots of acceleration force but low speed, in high gear you have lots of speed but low acceleration force. The force is like voltage and the speed like current. Why is this important? Consider the Niagra Falls power plant. Not many people live near there, but NYC is close enough it can use that power. So some of that power needs to go a few hundred miles.
But if you send a lot of current over a wire (like current through a light bulb) you create heat and lose electricity. But near a power plant they take the voltage and step it up to 500,000 volts with a transformer and send it over those big wires you see near some highways. Now the electricity travels hundreds of miles without making too much heat since its a lot of voltage but low current. After getting to the destination, another set of transformers steps that 500,000 volts back down to 100,000 and then 13,000 and then the 240 volts and 120 volts you have in your house. You see the transformer near your home because the electric company keeps the voltage high as long as it can to keep the losses in heat to a minimum.
So AC wins because the transformer allows the electricity to be transmitted long distances with low losses. Which means just a few power plants can power large areas, very evident with the recent blackout in the northeast part of the US from OH to NY or California a few years back. Had Edison won, there would be a power plant every 5-10 blocks, and the rural population would still be lighting lanterns at night or using tons of batteries since it would cost too much to build a power plant for 20 people.
Now, let's say you want to make high-voltage DC. Take an audio amplifier - its a pretty complicated device. A high-power car stereo amplifier takes the DC from the car battery, converts it to AC to run through a transformer to make a higher AC voltage, and then converts the transformer's AC output back into a high DC voltage, then turns that DC back into an AC signal that follows the music and sends that AC to the speakers. They don't seems like such different worlds anymore do they, AC and DC?
Hope that helps clear up why AC is usually associated with high voltage and DC with low voltage, even though they are both able to do the same things and each have useful and unique features.
Cliff
