Question

why when i connect the wire to bulb.. the voltage decrease?

Answer 1

are you referring to the terminal voltage across the wire? and the bulb is your load?

Answer 2

@athin

Answer 3

ok... it is usually the case among power source or any power supply... the reason behind there is the effect of load or loads to the voltage regulation of power supply... the bulb completes the circuit or close the circuit... current will flow thru' the bulb and a voltage will be present across it... as well as voltage drop will be present to the wires used in the circuit due to the wire resistances... once a current flows within the circuits... there is a supply of voltage all thru' out the loads across the power source.

Answer 4

@Orion1213 when i use battery light up the bulb.. the voltage decrease from 1.45V to 1.01V... than whwn i use salt water the volt decrease from 1.45v to 0.07v ... using salt water my bulb cannot light

Answer 5

it seems there is a big voltage drop thru' the wire electrodes and for the salt water, i made a little research on using it as the source of energy and i find this... this might help you to answer your question http://www.miniscience.com/projects/airbattery/

Answer 6

tq... i already see that page,.... in my experiment i use aluminum and copper... with the same surface of electrode... and my bulb is 2.5 v....
when i use LED to light up... the voltage are not happen... its still same... but the bulb... i loss to think what the problem... i really need halp

Answer 7

chemical reaction between materials and elements you used is needed here to determine the problem in your experiment...

Answer 8

sorry i cannot help you further beyond this point. Other out there might have other findings in this experiment. Wish you luck.

Answer 9

its ok... tq for helping...

Answer 10

Don't overlook the internal resistance of your source. The voltage drop across this internal resistance as a result of current flow in your completed circuit will result in an internal voltage drop that will reduce the voltage at the source terminals, while voltage drop as a result of wire resistance will reduce the voltage applied to the load.

Answer 11

The resistance of the wires is probably not significant in this case.

I think @radar has the key point - when no current is flowing you measure the terminal voltage of th esource.

However once the circuit is complete the current has to flow THROUGH the internal resistance of the source, and hence the measured terminal voltage is lower.

A salt water battery has high internal resistance and hence cannot deliver high currents

Answer 12

http://data.energizer.com/PDFs/BatteryIR.pdf

see this for more info..

Answer 13

@MrNood A very interesting link, it seemed uusual that they used AC to obtain the internal resistance of the battery, when it is a DC source! I learned something, thanks.

Answer 14

me too...