Batteries in series and parallel
In the Primary Connections Year 6 unit Circuits and Switches, students learn about how electrical energy is transferred, transformed and generated. Download the Circuits and Switches unit now for hands-on investigations into electrical circuits. How can batteries be connected in circuits? Basically, they can be connected in series or in parallel. The resultant voltage and current can be calculated by using a few simple rules. Battery terminals A standard single dry cell battery produces a voltage of 1.5 Volt, with
its current dependent on the size of the cell. The bigger the cell, the
bigger the current.
It's important to connect the batteries with their terminals in the correct order. Batteries in series need to be connected with the positive end of one battery to the negative end of the next battery. If they are incorrectly connected, the batteries will cancel out each other's energy and quickly flatten each other. Batteries correctly placed in series, positive to negative, will add their output voltages, producing a greater voltage. Voltage and current produced by batteries
in series Batteries with voltages greater than 1.5 volts are made up of cells connected in series inside a single case. In the 9 volt battery above, there are six cells connected in series. The calculation is 6 × 1.5 Volt = 9 Volt. When batteries are connected in series the flow of electrons, as measured by the current, is the same anywhere in the circuit. A 9 Volt battery will produce a voltage 6 times larger than a single 1.5 Volt battery in the same circuit, but the current in each circuit will be the same no matter where the current is measured. This happens because the batteries are arranged in a line, and like water flowing through different hoses connected in a line, what goes in one end must come out the other. The same electrons must flow through all the batteries at the same rate, so the current must be the same in each battery and in each part of the circuit. Batteries in parallel Remember the voltage increases when batteries are in series, but with batteries in parallel this is not the case. When two or more batteries are placed in parallel, the voltage in the circuit is the same as each individual battery. That is two, three, four or more 1.5 volt batteries in parallel will produce a voltage of 1.5 Volts! In a parallel circuit, individual electrons can only pass through one of the alternative paths and batteries at a time, thus each electron can only gain energy from one of the batteries in the circuit. As voltage is a measure of the energy carried by the electrons in the circuit, the increase in voltage for each electron in the circuit is the same as if they had passed through only one battery. What is the purpose of batteries in
parallel? A summary of batteries in series
When batteries are connected in parallel, the voltage remains the same, but the current that can flow in the circuit increases.
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