Technical Science - Term 4 - Week 7

An electrical circuit is a closed loop that allows current to flow from a power source through various components. The basic components of a circuit include resistors, capacitors, inductors, and power sources. Understanding how these components interact is crucial for analyzing circuit behavior.

Ohm's Law states that the current (I) flowing through a conductor between two points is directly proportional to the voltage (V) across the two points and inversely proportional to the resistance (R) of the conductor. This relationship is expressed by the formula V = I × R. This law is fundamental in calculating the values of voltage, current, and resistance in electrical circuits.

In a series circuit, components are connected end-to-end, so the same current flows through all components, but the total resistance is the sum of individual resistances. In contrast, in a parallel circuit, components are connected across the same voltage source, allowing multiple paths for current. The total resistance in a parallel circuit can be calculated using the formula 1/R_total = 1/R1 + 1/R2 + ... + 1/Rn.

Consider a circuit with a voltage of 12V and a resistance of 4Ω. To find the current, we apply Ohm's Law: I = V/R = 12V / 4Ω = 3A. This means that a current of 3 amperes flows through the circuit.

If we have three resistors in series with values of 2Ω, 3Ω, and 5Ω, the total resistance is R_total = R1 + R2 + R3 = 2Ω + 3Ω + 5Ω = 10Ω. This total resistance affects the current flowing through the circuit.

For two resistors in parallel, say 6Ω and 3Ω, the total resistance can be calculated as follows: 1/R_total = 1/R1 + 1/R2 = 1/6 + 1/3. Finding a common denominator gives us 1/R_total = 1/6 + 2/6 = 3/6, thus R_total = 2Ω.

Let's work through a problem together. A circuit has a voltage of 24V and a resistance of 8Ω. What is the current? Using Ohm's Law, I = V/R = 24V / 8Ω = 3A. Now, try calculating the current for a circuit with 30V and 10Ω resistance.

In a series circuit with resistors of 4Ω, 6Ω, and 10Ω, let's find the total resistance. R_total = R1 + R2 + R3 = 4Ω + 6Ω + 10Ω = 20Ω. Now, if the voltage is 40V, what is the current? I = V/R_total = 40V / 20Ω = 2A.

Consider two resistors in parallel, 12Ω and 4Ω. Calculate the total resistance. Using the formula, 1/R_total = 1/12 + 1/4. Finding a common denominator gives us 1/R_total = 1/12 + 3/12 = 4/12, so R_total = 3Ω. Now, if the voltage is 24V, what is the current?

1. A circuit has a voltage of 15V and a resistance of 5Ω. Calculate the current. 2. Find the total resistance of three resistors in series: 3Ω, 7Ω, and 2Ω. 3. Calculate the total resistance of two resistors in parallel: 8Ω and 2Ω. 4. If a circuit has a total resistance of 10Ω and a voltage of 50V, what is the current?

1. A series circuit has a total voltage of 24V and consists of two resistors: R1 = 4Ω and R2 = 8Ω. Calculate the current flowing through the circuit. 2. In a parallel circuit with resistors of 6Ω and 3Ω, if the voltage is 18V, find the current through each resistor.

• V = I + R
• V = I × R
• V = I / R
• V = R / I

Answer: V = I × R

Ohm's Law states that voltage equals current multiplied by resistance.

• R_total = R1 + R2 + R3
• R_total = R1 × R2 × R3
• R_total = 1/(1/R1 + 1/R2)
• R_total = R1 - R2

Answer: R_total = R1 + R2 + R3

In a series circuit, the total resistance is the sum of all individual resistances.

• It decreases
• It increases
• It remains the same
• It becomes zero

Answer: It increases

Adding more branches in a parallel circuit provides additional paths for current, increasing the total current.

Answer: 2A

Using Ohm's Law, I = V/R = 10V / 5Ω = 2A.

Answer: 3Ω

Using the formula 1/R_total = 1/4 + 1/12 gives R_total = 3Ω.

• It doubles
• It halves
• It remains the same
• It quadruples

Answer: It doubles

According to Ohm's Law, if voltage increases and resistance remains constant, current will also increase proportionally.

• Resistor
• Capacitor
• Inductor
• Transistor

Answer: Capacitor

A capacitor is designed to store electrical energy in an electric field.