Recent content by Joel Kee

V1=[R1/(R1+R2)]V My bad.

My bad, the eqs are supposed to be multiplied with the total voltage.

Homework Statement I'm trying to calculate the voltage drop across a 60uF and a 30uF capacitor in series, powered by 60V. Is the formula for voltage drop across capacitor opposite of the formula for resistor, where resistor is R1=R1/(R1+R2) while capacitor is C1=C2/(C1+C2)? Homework...

Alright! Any other advice?

Do you think that would work better, or wrapping copper wire with aluminium and salt water soaked tissue together, joined in series?

Will having multiple coins on one flat surface, piled on another set of coins on another flat surface on it, work?

Any idea how much voltage should my battery be in order for the LED to be about 3-4V?

Care to explain why the voltage of the battery doesn't really matter?

And how much voltage do you think I need to make it bright?

Can you explain more on why? And why does a normal battery make it light up so bright then?

UPDATE : The LED lights up! But it's really dim. Any idea how to make it brighter other than add more coins? P/s I still don't get why 5v isn't enough to make this LED light up brightly.

Thanks for the reply! I have almost lost faith in this project, so thanks for replying. I tried using a buzzer with this coin battery, yet no sound is produced. I shall try the LED in a dark room though. Any other advice?

Homework Statement I'm currently doing a mini project as an assignment in my engineering course. I tried replicating the coin battery, where I stack a piece of cardboard soaked in black vinegar (couldn't find white vinegar), a piece of aluminium foil, then a 20 sen coin (Malaysian...