Technical Science - Term 4 - Week 9

An electrical circuit is a closed loop that allows current to flow from a power source through various components and back to the source. The main components of a circuit include a power source (like a battery), conductors (wires), and loads (like resistors or light bulbs). Understanding how these components interact is crucial for analyzing and designing circuits.

There are two primary types of circuits: series and parallel. In a series circuit, components are connected end-to-end, so the same current flows through each component. In contrast, a parallel circuit has components connected across common points, allowing multiple paths for current to flow. This distinction affects how voltage and current are distributed in the circuit.

Ohm's Law is a fundamental principle in electronics, expressed as V = IR, where V is voltage, I is current, and R is resistance. This law allows us to calculate one of these values if the other two are known. Understanding Ohm's Law is essential for troubleshooting and designing circuits.

Consider a series circuit with a 12V battery and two resistors of 4Ω and 6Ω. The total resistance (R_total) is R1 + R2 = 4Ω + 6Ω = 10Ω. Using Ohm's Law, the current (I) can be calculated as I = V/R_total = 12V/10Ω = 1.2A. This current flows uniformly through both resistors.

In a parallel circuit with a 12V battery and two resistors of 4Ω and 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, which simplifies to R_total = 2.4Ω. The current through each resistor can then be calculated using Ohm's Law, showing that different paths allow for different current values.

Let's work together on a problem. We have a series circuit with a 9V battery and two resistors of 3Ω and 6Ω. First, calculate the total resistance. Then, apply Ohm's Law to find the current flowing through the circuit. Discuss your findings with a partner and compare your calculations.

Now, let's analyze a parallel circuit with a 12V battery and three resistors of 2Ω, 3Ω, and 6Ω. Calculate the total resistance and then determine the current through each resistor. Work in pairs to solve this problem and share your results with the class.

Design your own circuit using a 15V battery and at least three resistors of your choice. Calculate the total resistance, current, and voltage across each resistor. Prepare a brief presentation to explain your circuit design and calculations to the class.

Complete the following problems independently: 1) A circuit has a voltage of 24V and a resistance of 8Ω. What is the current? 2) If a circuit has a current of 3A and a resistance of 12Ω, what is the voltage? Show your work for each problem.

• Volts
• Amperes
• Ohms
• Watts

Answer: Ohms

Resistance is measured in Ohms, which quantifies how much a material opposes the flow of electric current.

• The same through all components
• Different in each component
• Zero
• Only flows through one component

Answer: The same through all components

In a series circuit, the same current flows through each component because they are connected end-to-end.

Answer: V = IR

Ohm's Law states that the voltage (V) across a conductor is equal to the product of the current (I) flowing through it and the resistance (R) of the conductor.

• It increases
• It decreases
• It stays the same
• It becomes infinite

Answer: It decreases

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

Answer: 2A

Using Ohm's Law (I = V/R), the current is calculated as I = 10V/5Ω = 2A.

• Resistor
• Capacitor
• Inductor
• Transistor

Answer: Capacitor

A capacitor stores electrical energy in an electric field, allowing it to release energy when needed.

• 3A
• 12A
• 48A
• 0.33A

Answer: 3A

Using Ohm's Law (I = V/R), the current is I = 12V/4Ω = 3A.