A simple circuit - 2 lamps in parallel connection dim

[fawk3s]

So I made this really simple circuit - a battery, some wires and a small light bulb. Now when I connected another light bulb with this light bulb, both of them where burning a tad dimmer than when there was only one lamp in the circuit.
Why is that? The voltage and the amperage should stay the same in both. Shouldnt they?

Thanks in advance,
fawk3s

 

[K^2]

It's because of resistance in battery itself. You can model the behavior of real battery in a circuit by having a small resistance in series with an ideal battery. When you add a second bulb, current increases. That means higher voltage across resistor, and therefore, lower voltage across the two light bulbs.

You can alleviate that by adding a second battery in parallel with the original. The two light bulbs will then shine just as bright as a single light bulb with single battery.

 

[Feldoh]

Light bulbs are basically resistors. Perhaps this helps?

 

[Buckleymanor]

Does it not allso depend on how your simple circuit is configured.
Is the wireing in parallel or series.
Sorry seen the title me being dim.
Try connecting the lightbulbs in series pos battery, wire, lightbulb, wire, lightbulb, wire, battery neg.Should stay brighter.

 

[fawk3s]

It's because of resistance in battery itself. You can model the behavior of real battery in a circuit by having a small resistance in series with an ideal battery. When you add a second bulb, current increases. That means higher voltage across resistor, and therefore, lower voltage across the two light bulbs.

You can alleviate that by adding a second battery in parallel with the original. The two light bulbs will then shine just as bright as a single light bulb with single battery.

Thanks mate, I think I get it.

 

[K^2]

Try connecting the lightbulbs in series pos battery, wire, lightbulb, wire, lightbulb, wire, battery neg.Should stay brighter.

No, if you connect them in series, they will be much dimmer, and likely won't light at all. You would effectively be cutting voltage across each one in half.

 

[fawk3s]

Mostly when connecting in series it will end up dimmer indeed. But when randomly calculating I found out that when playing around with 2 lightbulbs with resistance of 10 ohms, and a battery with 10 ohms, and with a voltage of 40 V, the voltage and amperage in both of the bulbs is the same, making no difference which way you connect them.
But these are, ofcourse, random numbers.

 

[K^2]

Keep in mind that realistically, the resistance in the battery is significantly lower than in a light bulb, so connecting multiple bulbs in parallel won't have as much of an effect on current through each as connecting them in series.

Also, the resistance in the filament depends on the temperature, and temperature depends on the current flowing through the filament. So that complicates things even more.