Technical Science - Term 2 - Week 10

An electrical circuit is a closed loop that allows electric current to flow. It consists of a power source, conductors, and a load. The power source, such as a battery or generator, provides the energy needed to move electrons through the circuit. Understanding how these components interact is crucial for analyzing and designing circuits.

Ohm's Law is a fundamental principle in electronics that relates voltage (V), current (I), and resistance (R) in a circuit. It is expressed as V = I × R. This relationship allows us to calculate one of the three variables if the other two are known. For example, if a circuit has a voltage of 12 volts and a resistance of 4 ohms, the current can be calculated as I = V/R, which equals 3 amperes.

In a series circuit, components are connected end-to-end, so the same current flows through all components. The total resistance is the sum of individual resistances. In contrast, a parallel circuit has components connected across the same voltage source, allowing multiple paths for current. The total resistance in a parallel circuit is less than the smallest individual resistance, and the voltage across each component is the same.

Consider a circuit with a voltage of 24 volts and a resistance of 6 ohms. To find the current, we apply Ohm's Law: I = V/R. Substituting the values, we get I = 24V / 6Ω = 4A. Thus, the current flowing through the circuit is 4 amperes.

Suppose we have three resistors in series: R1 = 2Ω, R2 = 3Ω, and R3 = 5Ω. The total resistance (R_total) is calculated as R_total = R1 + R2 + R3 = 2Ω + 3Ω + 5Ω = 10Ω. Therefore, the total resistance in this series circuit is 10 ohms.

For a parallel circuit with two resistors, R1 = 4Ω and R2 = 6Ω, the total resistance can be calculated using the formula 1/R_total = 1/R1 + 1/R2. Thus, 1/R_total = 1/4 + 1/6. Finding a common denominator, we get 1/R_total = 3/12 + 2/12 = 5/12. Therefore, R_total = 12/5 = 2.4Ω.

In groups, calculate the current for a circuit with a voltage of 30 volts and a resistance of 10 ohms. Use Ohm's Law to find the answer and discuss how changes in resistance would affect the current.

Using a circuit diagram provided, identify the total resistance in a series circuit with three resistors: 5Ω, 10Ω, and 15Ω. Work together to calculate the total resistance and discuss how the current would behave in this circuit.

Given a parallel circuit with two resistors of 8Ω and 12Ω, calculate the total resistance. Discuss how the voltage across each resistor compares and how this affects the overall current in the circuit.

Individually, solve the following problems: 1) Calculate the current in a circuit with a voltage of 50 volts and a resistance of 25 ohms. 2) Determine the total resistance in a series circuit with resistors of 3Ω, 4Ω, and 6Ω. 3) Find the total resistance in a parallel circuit with resistors of 5Ω and 10Ω.

Research a household appliance that uses electrical circuits. Write a short paragraph explaining how it operates in terms of series and parallel circuits, and how Ohm's Law applies to its functioning.

Design a simple circuit diagram that includes a power source, two resistors in series, and a switch. Label all components and calculate the total resistance and expected current if the voltage is 12 volts.

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

Answer: V = I × R

Ohm's Law states that voltage is equal to the current multiplied by resistance.

• The sum of individual resistances
• The average of individual resistances
• The product of individual resistances
• Always equal to the smallest resistance

Answer: The sum of individual resistances

In a series circuit, the total resistance is calculated by adding all individual resistances together.

• It increases
• It decreases
• It remains the same
• It doubles

Answer: It decreases

Adding more resistors in parallel provides additional paths for current, which decreases total resistance.

Answer: 4 A

Using Ohm's Law, I = V/R = 60V / 15Ω = 4A.

Answer: 10 Ω

Total resistance in series is R_total = R1 + R2 + R3 = 2Ω + 3Ω + 5Ω = 10Ω.

• 3 A
• 4 A
• 6 A
• 12 A

Answer: 3 A

Using Ohm's Law, I = V/R = 12V / 4Ω = 3A.

Answer: In series circuits, current flows through each component sequentially, while in parallel circuits, components are connected across the same voltage source, allowing multiple paths for current.

This fundamental difference affects how voltage and current behave in each type of circuit.