Technical Science - Term 3 - Week 2

Electrical circuits consist of various components, including resistors, capacitors, inductors, and power sources. Resistors limit the flow of current, capacitors store electrical energy, and inductors oppose changes in current. Power sources, such as batteries or power supplies, provide the necessary voltage to drive the current through the circuit.

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 the same voltage source, allowing multiple paths for current to flow. Understanding these configurations 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 can be expressed with the formula V = I × R. Mastering this law is essential for solving electrical circuit problems.

Consider a series circuit with a 12V battery and two resistors, R1 = 4Ω and R2 = 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 means that 1.2A 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 (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.

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

Now, let's analyze a parallel circuit. We have a 12V battery and two resistors, R1 = 6Ω and R2 = 12Ω. Calculate the total resistance using the parallel formula. After finding R_total, determine the current flowing through each resistor using Ohm's Law. This will help you understand how current divides in parallel circuits.

For independent practice, solve the following problems: 1) A series circuit with a 15V battery and resistors R1 = 5Ω and R2 = 10Ω. Calculate the total resistance and current. 2) A parallel circuit with a 24V battery and resistors R1 = 8Ω and R2 = 4Ω. Find the total resistance and the current through each resistor. Show your calculations clearly.

Design a simple circuit using at least one resistor, one capacitor, and a power source. Describe the purpose of each component and how they interact within the circuit. Present your design to the class, explaining the expected behavior based on Ohm's Law and circuit principles.

• 10Ω
• 8Ω
• 5Ω
• 3Ω

Answer: 10Ω

In a series circuit, total resistance is the sum of all resistances: 2Ω + 3Ω + 5Ω = 10Ω.

• It increases
• It decreases
• It remains the same
• It stops completely

Answer: It decreases

In a parallel circuit, if one path is broken, the total current decreases as there are fewer paths for current to flow.

Answer: V = I × R

Ohm's Law relates voltage (V), current (I), and resistance (R) in an electrical circuit.

• 3A
• 2A
• 4A
• 1A

Answer: 3A

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

Answer: The total resistance decreases.

Adding more resistors in parallel provides additional paths for current, reducing the overall resistance.

• Resistor
• Capacitor
• Inductor
• Battery

Answer: Capacitor

A capacitor stores electrical energy in an electric field, unlike resistors which dissipate energy.

Answer: A series circuit is a circuit where components are connected end-to-end, so the same current flows through each component.

In a series circuit, the current is the same through all components, and the total voltage is the sum of the voltages across each component.