what is the voltage supply to a bulb that is connected to 3 batteries (3v, 9v, 12v) in a parellel circuit?

Answer 1

Batteries can be connected in Parallel and it's often done in boats to increase current. However the batteries must be of the same rating and preferably same condition and charge.

In series the current is constant as it would be difficult, for 2 amps to flow in one and 3 amps in another unless there was external leakage. Since current is the same voltage is accumulative in a series circuit.

In a Parallel circuit the voltage at the tie point has to be the same, other wise the higher voltage would become a source for the lower voltage. It would create a circuit within the power supply. Since the voltage must be the same the current is accumulative.


Looking at your question again, hypothetically you would have an 8 volt power supply. The parallel voltage is an average of the sources, i.e. 24/3 = 8V. You would not be operating with efficient current though.

Answer 2

The circuit might be parallel for the lamp but the batteries have to be in series to avoid destroying each other. Since batteries in series add voltage the total voltage across the bulb = 3+9+12 = 24 volts.

Answer 3

the last answer gave you the theoretical answer (8v) which is the average of the three. But like they both said and to put it in simple terms.. when you hook up htat 12v to the 3v in parallel you are going to get a very warm 3v battery as the 12v pushes voltage into it to try to balance it.

Think of it as three jars on a level shelf .. each with greatly different volumes of water. If you hook up a siphon to each of them, water will start to flow into the one with the least amount.... that water is the same as electric current in your circuit...

If the jars are flimsy enough, the smaller one will burst.