Technical Science - Term 1 - Week 8

An electrical circuit consists of several key components: a power source (like a battery), conductors (wires), and loads (devices that use electricity, such as bulbs or motors). The power source provides the necessary voltage to push the current through the circuit. Conductors allow the flow of electricity, while loads convert electrical energy into other forms of energy, such as light or motion.

There are two primary types of electrical circuits: series and parallel. In a series circuit, components are connected end-to-end, meaning the same current flows through each component. If one component fails, the entire circuit is interrupted. In contrast, a parallel circuit has multiple paths for current to flow. If one path fails, current can still flow through other paths, keeping the circuit operational.

Ohm's Law is a fundamental principle in electronics that relates voltage (V), current (I), and resistance (R) in a circuit. It states that V = I × R. This means that the voltage across a conductor is directly proportional to the current flowing through it, with the resistance being the constant of proportionality. Understanding this law is crucial for calculating the values of voltage, current, and resistance in various circuit configurations.

Consider a series circuit with a 12V battery and two resistors, R1 = 4Ω and R2 = 2Ω. The total resistance (R_total) is R1 + R2 = 4Ω + 2Ω = 6Ω. Using Ohm's Law, the current (I) can be calculated as I = V/R_total = 12V/6Ω = 2A. This means that 2A of current flows through the entire circuit.

In a parallel circuit with a 12V battery and two resistors, R1 = 4Ω and R2 = 6Ω, the total resistance (R_total) can be calculated using the formula 1/R_total = 1/R1 + 1/R2. Thus, 1/R_total = 1/4 + 1/6 = 5/12, leading to R_total = 12/5 = 2.4Ω. The current through each resistor can then be calculated using Ohm's Law, showing how current divides in a parallel circuit.

Let's work together on a problem. We have a series circuit with a 9V battery and two resistors: R1 = 3Ω and R2 = 3Ω. First, calculate the total resistance: R_total = R1 + R2 = 3Ω + 3Ω = 6Ω. Now, apply Ohm's Law to find the current: I = V/R_total = 9V/6Ω. What is the current flowing through the circuit?

In pairs, discuss the following scenarios: 1) A flashlight that turns off when one bulb is removed. 2) A string of holiday lights that remain lit even if one bulb is removed. Identify which scenario represents a series circuit and which represents a parallel circuit. Share your reasoning with the class.

Complete the following problems independently: 1) Calculate the current in a circuit with a 24V battery and a total resistance of 8Ω. 2) Draw a diagram of a parallel circuit with three resistors (2Ω, 4Ω, and 6Ω) connected to a 12V battery. Label all components and calculate the total resistance.

Choose a real-world application of electrical circuits (e.g., home wiring, electronic devices) and write a short report on how circuits are used in that application. Include diagrams and explain the types of circuits involved.

• To store electrical energy
• To limit current flow
• To increase voltage
• To convert energy

Answer: To limit current flow

Resistors are used in circuits to control the amount of current that flows, protecting components from excessive current.

• The circuit remains operational
• The circuit is interrupted
• Only the failed component stops working
• The voltage increases

Answer: The circuit is interrupted

In a series circuit, all components are connected in a single path; if one fails, the entire circuit stops functioning.

Answer: V = I × R

Ohm's Law states that voltage (V) is equal to the current (I) multiplied by the resistance (R).

• 2.4Ω
• 10Ω
• 24Ω
• 1.5Ω

Answer: 2.4Ω

The total resistance in a parallel circuit can be calculated using the formula 1/R_total = 1/R1 + 1/R2.

Answer: The total current increases.

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

• Same current flows through all components
• Voltage is the same across all components
• If one component fails, the circuit stops
• All components must be identical

Answer: Voltage is the same across all components

In a parallel circuit, each component experiences the same voltage, while the current can vary.