The potential difference between two terminals in a circuit is the difference in the amount of energy that the batteries have. Here batteries play the role of charge carriers.
In a circuit, current is needed to run the devices. And there will be no current in a circuit without any source. So, a battery contains an amount of voltage that provides current to the circuit.
What Is the Potential Difference Between The Terminals Of The Battery?
The potential difference between the terminals of a battery is measured in Volts and is also called voltage. If the electric potential difference between two points is one volt, then moving one Coulomb of charge between two points gains one joule of potential energy. So, 1 Volt = 1 Joule/ 1 Coulomb.
If we consider the two points as A and B, where A is the ending point and B is the starting point, then the charge will flow from B to A. Let us take PE as potential energy. So, the electric potential difference in equation form is,
ΔV = VB – VA = Work/Charge = Δ PE/Charge
Again, you can use Ohm’s law to figure out the potential difference using current and resistance from the circuit. It will be,
[V = I x R] V (volts) = I (amps) x R (Ω)
You can also measure the voltage by using Power,
V = P/I, V = √ (P x R)
Examples of Electric Potential Diagram
In circuit-A, the potential difference of the battery is 1.5V. Energy flows from higher potential to lower potential, and in the way of the flow, there is a bulb. So, we see voltage drop across the bulb as the voltage is spent on the bulb. Here C and D are 0V.
Similarly, in circuit-B, the 6V battery is running two bulbs. But here C and D have the voltage to power up the second bulb. In this case, E and F are 0V. For both cases, the positive terminal of the battery has an electric potential equal to the battery’s voltage rating.
Roll of a Battery in a Circuit
The batteries simply provide the energy required to perform work on the charge in order to shift it from the negative to the positive terminal. It can keep an electric potential difference across the two ends of the external circuit by giving energy to the charge.
After reaching the high potential terminal, the charge will naturally flow through the wires to the low potential terminal. The flow of charge through an electric circuit is similar to the flow of water in a water park. As it pumps the charge from the negative to the positive terminal, we see current flowing through the devices.
How to Check a Battery Voltage
To check a battery’s voltage, you will need a Voltmeter. Connect the black probe of the voltmeter to COM and the red probe to mAV. Set the multimeter’s DC (direct current) range according to your measurement. Almost all portable electronics operate on direct current rather than alternating current.
Connect the black probe to the earth or ‘-‘ of the battery and the red probe to the power or ‘+’. Squeeze the probes against the positive and negative terminals of the AA battery with light pressure. Now the display should show the potential difference between the terminals of the battery.
Setting the Meter Knob
A common question that can arise in your head is, why does the meter knob say 20V and not 10V? It is because, if you want to measure a voltage less than 20V, you have to use the 20V setting. You will be able to read from 2.00 to 19.99 with this. And it is the same for the rest of the setting.
The Way a Battery Produces Potential Difference
A battery is powered by the energy released by internal chemical reactions. When a battery is “charged,” energy is stored in the chemical bonds of the components, and charges flow through the electrolyte. This results in the formation of an electric potential or field.
When a battery is charged and a load is applied across its terminals, the potential difference causes energy to be released when chemical bonds are broken, causing the battery to lose potential.
Frequently Asked Questions
Why is electric potential important?
Electric potential is more practical than electric field because potential differences, at least on conductors, can be measured directly. Electric potentials and electric fields are related in a given region, and either can be used to represent the electrostatic properties of space.
What is load in a circuit?
An electrical load is a component or section of a circuit that consumes electric power, such as household appliances and lights. The phrase can also refer to the amount of power used by a circuit. In contrast, a power source, such as a battery or generator, generates power.
When measuring the potential difference of a battery using the voltmeter, it is recommended to stick to DC circuits. Although most multimeters can measure AC systems, AC circuits are not a hundred percent safe.