Some random questions...

[xenoxion]

...

 

[Nigel Goodwin]

I'm new to electricity, and I've just got a few general questions...

1. Can I charge a 400V capacitor by using 2 200V AC power sources? Would I have to connect them in a series or parallel to do this?

In series, don't forget though - you need DC to charge a capacitor.

2. What happens if I use a power source to charge a capacitor that isn't at that capacitor's voltage rating (eg.- charging a 10V cap with a 1.5V AA battery). Will it charge at max voltage and just take longer, or will it charge normally just at 1.5V instead of 10V, or something else?

It will only charge to 1.5V, it can't charge any higher than the source voltage.

3. How many (milli)amps do comman battery sizes put out? Where can I find the amperage of AA, AAA, C, D, and 9v batteries?

It varies between different types of batteries. what exactly do you want to know - the AH rating (which is occasionally given) or the maximum current available (which isn't). Also, why do you want to know?.

4. How bright of an LED would I need to make a flashlight out of?

You can only make very feeble ones - although there are quite bright LED's beginning to appear now - but still nowhere near a bulb!.

5. How long does it take to charge a 1 Farad capacitor?

Depends on the source resistance feeding it, the formula is T=C*R, where T is in seconds, C in farads, and R in ohms. For full charge it's usually considered to take 5T seconds. So a 1F capacitor fed from 1 ohm, would take 5 seconds to charge.

 

[xenoxion]

Thanks! Just one more thing though, can I just use diodes to convert AC to DC to charge the capacitor?

It varies between different types of batteries. what exactly do you want to know - the AH rating (which is occasionally given) or the maximum current available (which isn't). Also, why do you want to know?.

I wanted to know the maximum current available so I can use it my calculations.

 

[Nigel Goodwin]

Thanks! Just one more thing though, can I just use diodes to convert AC to DC to charge the capacitor?

Yes, you can - the rating of the diodes depends on lots of factors though, probably best to post the circuit of what you are trying to do.

I wanted to know the maximum current available so I can use it my calculations.

This isn't usually something required in calculations, and would vary a great deal - again, tell us exactly what you are trying to do, and what calculations you are wanting to use.

 

[grrr_arrghh]

4. How bright of an LED would I need to make a flashlight out of?

There are quite a few on the market that use (usually) three or five ultra bright LEDs (because this uses less power than a bulb). However, this only provides enough light for maybe reading, or perhaps seeing what you are doing inside a tent. Unfortunately, anything more than that (running at night, cooking by etc) you will need a proper torch with a normal bulb in it.

LED torches are very light (few batteries needed) so are quite useful as emergency torches, but thats about it.

Tim