Electrical Engineering: Basic Laws (4 of 31) What is Conductance?

Michel van Biezen

30 Oct 201502:34

Summary

TLDRThis video explains the concept of conductance, which is the ability of an element to conduct electrical current. Conductance is the inverse of resistance, meaning lower resistance results in higher conductance, and vice versa. The unit of conductance is the siemens (S), and it is defined as 1 ampere per volt. The video further discusses how conductance relates to Ohm's Law, where G = 1/R, and how it can be used in calculating power dissipation in a circuit. Different equations involving conductance, resistance, and power are explored to deepen understanding.

Takeaways

🔌 Conductance is the ability of an element to conduct electrical current.
🔄 Conductance is the inverse of resistance. Higher resistance means lower conductance and vice versa.
📏 Conductance is measured in units of Siemens (S), which is equivalent to 1 ampere per volt.
🔄 The symbol for conductance is derived from the Ohm symbol, reversed, and it can also be called a mho.
📐 Ohm's Law is key to understanding conductance, as it relates voltage (V), current (I), and resistance (R).
💡 Conductance (G) is defined as 1/R, meaning it represents how much current can flow per unit voltage.
⚡ Power dissipation can be expressed in multiple ways using conductance, such as P = I²/G.
🧩 When voltage and current are known, conductance can be calculated as G = I/V.
🔋 The power dissipation equations can be rewritten in terms of conductance for different circuit analysis approaches.
📊 Overall, understanding conductance helps analyze circuit behavior, especially how easily current flows.

Q & A

What is conductance?
-Conductance is the ability of an element to conduct electrical current. The more current it allows to flow through, the higher the conductance.
How is conductance defined in relation to resistance?
-Conductance is defined as the inverse of resistance. The lower the resistance, the higher the conductance.
What is the unit of conductance?
-The unit of conductance is the Siemens (symbolized as S), and 1 Siemens is equal to 1 ampere per volt.
What is the symbol for the unit of conductance in the script?
-The symbol for the unit of conductance in the script is 'mho', which is the ohm symbol upside down.
How is the relationship between current (I), voltage (V), and resistance (R) expressed in Ohm's law?
-Ohm's law is expressed as I = V/R, which means the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them.
How can conductance (G) be expressed using Ohm's law?
-Using Ohm's law, conductance (G) can be expressed as G = 1/R. Since G is the inverse of resistance, it can also be written as G = I/V.
What is the power dissipation equation in terms of conductance?
-The power dissipation equation in terms of conductance is P = I^2 * R. However, since G = I/V, power can also be expressed as P = G * V^2.
How can power dissipation be related to conductance and voltage?
-Power dissipation can be related to conductance and voltage by the equation P = G * V^2, showing that power is directly proportional to the square of the voltage and the conductance.
What does it mean when it's said that 'conductance is the inverse of resistance'?
-It means that as resistance decreases, conductance increases, and vice versa. They are inversely proportional to each other.
How does the script describe the relationship between power, current, and conductance?
-The script describes that power (P) is equal to the product of current (I) and voltage (V), and since G = I/V, power can also be expressed as P = G * V^2, showing that power is directly proportional to the square of the voltage and the conductance.
What is the significance of the mho as a unit of conductance?
-The mho, being the inverse of the ohm, signifies the reciprocal relationship between resistance and conductance, making it a convenient unit for expressing conductance.

Outlines

00:00

⚡ Introduction to Conductance

The video introduces the concept of conductance, defined as the ability of an element to conduct electrical current. Conductance is the inverse of resistance: the lower the resistance, the higher the conductance, and vice versa. The unit of resistance is ohms, while the unit for conductance is siemens (S), sometimes represented as 'mho' (ohm spelled backward). One siemen is equivalent to one ampere per volt, and the video also introduces the basic relationship between current (I), voltage (V), and resistance (R) using Ohm’s law.

🔄 Ohm's Law and Conductance Relation

The relationship between Ohm's law and conductance is discussed in more detail. Ohm's law states that I = V/R, and since conductance (G) is the inverse of resistance (G = 1/R), it can be expressed as G = I/V. The video further explains how this relationship can be used to understand how much current flows in a circuit given the voltage applied and the resistance present.

⚙️ Conductance and Power Dissipation

The video elaborates on how power dissipation in a circuit is related to conductance. Power (P) can be calculated using different formulas, such as P = I²R or P = V²/R. With conductance, power can also be expressed as P = I²/G. The video explores how replacing current (I) with conductance (G) in these equations allows for different interpretations of power dissipation in electrical circuits.

🔁 Summary of Conductance and Resistance

The video recaps the relationship between conductance and resistance, emphasizing that they are inversely related. The higher the resistance in a circuit, the lower the conductance, and vice versa. This inverse relationship is crucial for understanding electrical behavior in circuits and the dissipation of power. The video concludes by reiterating the importance of conductance in electrical systems.

Mindmap

Keywords

💡Conductance

Conductance is the measure of how easily an electrical current can pass through a material or component. It is the inverse of resistance, meaning that as resistance decreases, conductance increases. In the video, conductance is explained as the ability of an element to conduct electrical current. The higher the conductance, the more current can flow through the element. It is directly related to the video's theme as it is the central concept being discussed.

💡Resistance

Resistance is the measure of how much an element opposes the flow of electric current. It is the inverse of conductance, so a high resistance means a low conductance and vice versa. In the script, resistance is used to contrast with conductance, highlighting that lower resistance leads to higher conductance, which is key to understanding the relationship between these two properties.

💡Ohms

Ohms is the unit of measurement for electrical resistance. The script mentions that since the units for resistance are ohms, the unit for conductance is the inverse of ohms, symbolized as a mohm (ohm written in reverse). Ohms are used to quantify resistance, which is a fundamental concept in the video that helps explain conductance.

💡Mho

Mho, symbolized as '℧', is the unit of conductance. It is ohm written in reverse, indicating that 1 mho is equal to the inverse of 1 ohm. The script uses mho to explain the unit of conductance, emphasizing that 1 mho equals 1 siemens, which is another unit for conductance.

💡Siemens

Siemens, symbolized as 'S', is a standard unit for electrical conductance. The video script clarifies that 1 mho is equivalent to 1 siemens, which is used to measure the amount of current that can flow per unit voltage supplied to the circuit. Siemens is a key unit in the context of the video as it helps to quantify conductance.

💡Ohm's Law

Ohm's Law is a fundamental principle in electrical engineering that states the relationship between voltage (V), current (I), and resistance (R) in a circuit: V = I * R. The script uses Ohm's Law to explain how conductance (G) can be derived from resistance (R), showing that G = 1/R. This law is central to the video's discussion as it links conductance to other basic electrical concepts.

💡Ampere

Ampere, symbolized as 'A', is the unit of electric current. In the context of the video, ampere is used to define the siemens unit of conductance, which is 1 ampere per volt. The script mentions that the definition of a siemens or a mho is 1 amp per volt, making ampere a key unit in understanding conductance.

💡Volt

Volt, symbolized as 'V', is the unit of electric potential difference or voltage. The video script uses volt in the context of Ohm's Law and to define the unit of conductance (siemens), stating that conductance is the amount of current that can flow per unit voltage supplied to the circuit.

💡Power Dissipation

Power Dissipation refers to the conversion of electrical power into other forms of energy, such as heat, within a circuit. The script discusses power dissipation in relation to conductance, stating that power can be expressed as I^2 * R or V^2 / R, and since G = 1/R, power can also be expressed as I^2 / G. This concept is important in the video as it shows the practical implications of conductance in a circuit.

💡Inverse

Inverse, in the context of the video, refers to the mathematical operation of finding a value that, when multiplied by the original value, results in a product of one. The script explains that conductance is the inverse of resistance, with the formula G = 1/R. This concept is crucial for understanding how changes in resistance affect conductance.

Highlights

Conductance is the ability of an element to conduct electrical current; the more it allows current to flow, the higher the conductance.

Conductance is the inverse of resistance; lower resistance leads to higher conductance, and higher resistance leads to lower conductance.

The unit for conductance is the Siemens (S), which is equivalent to 1 ampere per volt.

The term 'mho' is also used for conductance, which is the ohm symbol written upside down and reversed.

Conductance (G) is defined as the reciprocal of resistance (R), G = 1/R.

According to Ohm’s law, I = V/R, and since G = 1/R, we can express G as I/V.

Power dissipation in a circuit can be expressed in multiple ways: P = I²R, P = IV, and P = V²/R.

By replacing I with G times V, power dissipation can also be expressed as P = G * V².

The definition of conductance as G = I/V implies that it directly relates to how much current flows per unit voltage.

Ohm’s law and the power dissipation equation can both be rewritten in terms of conductance (G).

Higher conductance means more current flows through the element for the same voltage.

Power dissipation can be expressed in terms of conductance as P = I² / G.

The relationship between resistance and conductance is crucial in understanding the behavior of electrical circuits.

Substituting values of conductance into Ohm’s law leads to simplified equations for analyzing circuit power dissipation.

In summary, conductance is a key parameter for describing how efficiently an element conducts electrical current, and it inversely correlates with resistance.