Potential Difference

The voltage difference between any two points in a circuit is known as the Potential Difference, and it is this potential difference that allows the current to flow.

We have previously examined the potential difference in our negative voltage generation article, you can check out this topic here.

Unlike the current that flows around a closed electrical circuit in the form of an electric charge, the potential difference does not move.

The unit of potential difference produced between the two points is called Volt and is usually defined as the potential difference that falls along a constant resistance of one ohm as a current of one amp passes through it.

In other words, 1 Volt equals 1 Amp times 1 Ohm, or usually V = I*R.

The Ohm Actstates that the current flowing through it for a linear circuit is proportional to the potential difference on it, so the larger the potential difference between any two points, the larger the current passing through it.

For example, the voltage on one side of a resistance with a resistance value of 10Ω is measured at 8V on the other side, so the potential difference on the resistance will be 3V, which will cause 0.3A current flow.

However, if the 8V side of the resistance was 40V, the potential difference on the resistance would be 40V – 5V = 35V, which would cause 3.5A current to flow.

For electrical circuits, the soil or soil potential is usually taken at zero volts (0V), and everything refers to this commonal point in the circuit, that is, reference is taken.In theory, it's like measuring height.We measure the height of the hills in a similar way by saying that the sea level is at zero meters, and then we compare the other points of the hill or mountain with that level.

Very similarly, we can call the common point in a circuit zero volts, and call it earth, zero volts, then all other voltage points in the circuit are compared or referred to that point of earth.The use of a common grounding or reference point in electrical schematic drawings makes the circuit simpler as it is understood that all connections to this point have the same potential.For example:

potential difference
Potential Difference

Since the unit of measure for Potential Difference is volt, the potential difference is mainly called voltage.As seen in the examples in resistance training, serially connected individual voltages can be added together to give us the sum of the "total voltage" of the circuit.Voltages between components that connect in parallel will always be of the same value, for example, as seen in the resistors in the parallel tutorial.

For serial connected voltages:

potential difference

For parallel connected voltages:

potential difference

Potential Difference Question Example 1

Using the Ohm Act, the current passing through a resistance can be calculated as follows:

Calculate the current passing through a resistance of 100Ω, one terminal connected to 50 volts and the other terminal to 30 volts.

The voltage in terminal A is equal to 50v and the voltage in terminal B is equal to 30v.Therefore, the voltage on the resistance is given as follows:

V A = 50v, V B = 30V, therefore, V A – V B = 50 – 30 = 20v

The voltage on the resistance is 20v, in which case the current passing through the resistance is given as follows:

I = V EU ÷ R = 20V ÷ 100Ω = 200mA

Voltage Divider Network

We know from previous lessons that by serially connecting resistances along a potential difference, we can produce a voltage dividing circuit that will give voltage ratios in each resistance according to the feed voltage throughout the total combination.

This is something that is often referred to as the Voltage Divider Network and applies only to serially connected resistorsbecause, as we see in the Resistances in Parallel tutorial, resistances that are connected in parallel form what is called a current dividing network.

potential difference
Voltage Divider

The circuit shows the principle of a voltage dividing circuit in which the R1, R2, R3 and R4 resistors refer to some common reference points (usually zero volts), in which the output voltage decreases along each resistance within the serial chain.

Thus, for any number of resistances connected to each other in series, by dividing the supply voltage into the total resistance of V S, R T will give the current flowing along the serial branch as follows: I = VS /RT , (Ohm Law).Then the individual voltage drops on each resistance can be calculated simply as follows: V = I*R here represents the R resistance value.

The voltage at each point increases according to the sum of the voltages at each point, from the supply voltage to the supply voltage of P1 , P2 , P3, etc., and we can also calculate individual voltage drops at any point without calculating the circuit current using the following formula.

Voltage Divider Formula

potential difference

The voltage to be found here V (x) is the resistance that produces the R (x) voltage, the R T is the total serial resistance and the V S supply voltage.

Potential Difference Question Example 2

In the above circuit, four resistors of R 1 = 10Ω , R 2 = 20Ω , R 3 = 30Ω and R 4 = 40Ω are connected to a DC source of 100 volts.Using the formula above, calculate voltage drops at points P1, P2, P3 and P4, as well as individual voltage drops along each resistance within the serial chain.

1. At various points, the voltages are calculated as follows:

potential difference

2. The individual voltage drops on each resistance are calculated as follows:

potential difference

Then, using this equation, we can say that the voltage falling along any resistance in a series circuit is proportional to the size of the resistance, and the total voltage falling through all resistors should be equal to the voltage source defined by Kirchhoff's Voltage Law.Thus, using the Voltage Divider Equation,for any number of serial resistors, voltage drop in any individual resistance can be found.

So far, we have seen voltage applied to a resistance or circuit and the current flowing through and around a circuit.But there is a third variable that we can also apply to resistances and resistance networks.It is a product of power, voltage and current, and the main unit of measure of power is wattage.

In the next lesson on resistances, we will examine the power spent (consumed) by resistance in the form of heat and the total power distributed by a resistance circuit, whether serial, parallel or a combination of the two.