Technical Science - Term 2 - Week 6

An electrical circuit is a closed loop that allows electric current to flow. The basic components of a circuit include a power source (like a battery), conductors (wires), and load devices (like bulbs or motors). Understanding these components is crucial for analyzing how circuits function and how to troubleshoot them.

There are two primary types of circuits: series and parallel. In a series circuit, components are connected end-to-end, meaning 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 behave in each type.

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 law allows us to calculate one of these quantities if the other two are known, making it essential for circuit analysis.

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 flows through each component in the series circuit.

In a parallel circuit with a 12V battery and 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 = 5/12, leading to R_total = 12/5 = 2.4Ω. The current through each resistor can then be calculated using Ohm's Law, showing that different currents flow through each branch.

Let's work together on a problem. We have a series circuit with a 9V battery and three resistors: R1 = 3Ω, R2 = 3Ω, and R3 = 3Ω. First, calculate the total resistance: R_total = R1 + R2 + R3. Next, use Ohm's Law to find the current flowing through the circuit. What is the total resistance and the current?

In pairs, look at the provided circuit diagrams and identify whether each is a series or parallel circuit. Discuss with your partner the implications of the circuit type on the current and voltage across each component. Be prepared to share your findings with the class.

Complete the following problems on your own: 1) A circuit has a 24V battery and two resistors in series, R1 = 8Ω and R2 = 4Ω. Calculate the current flowing through the circuit. 2) A parallel circuit has a 12V battery and two resistors, R1 = 6Ω and R2 = 3Ω. Find the total current supplied by the battery. Show all your calculations.

Design a simple circuit using at least one battery, two resistors, and a light bulb. Draw the circuit diagram and label all components. Calculate the total resistance, current, and voltage across each component. Be ready to present your design to the class.

• Ohm
• Volt
• Ampere
• Watt

Answer: Ohm

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 the battery

Answer: The same through all components

In a series circuit, the same current flows through each component because there is only one path for the current.

• Increases
• Decreases
• Remains the same
• Becomes infinite

Answer: Decreases

Adding more resistors in parallel decreases the total resistance because it provides additional pathways for current to flow.

Answer: V = I × R

Ohm's Law states that the voltage across a conductor is directly proportional to the current flowing through it, with resistance as the proportionality constant.

Answer: 2A

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

• Resistor
• Capacitor
• Battery
• Wire

Answer: Capacitor

While capacitors can be part of more complex circuits, they are not essential components in a basic electrical circuit.

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

Answer: It doubles