Technical Science - Term 3 - Week 10

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 circuits: series and parallel. In a series circuit, components are connected end-to-end, so 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, allowing the circuit to continue functioning.

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 component is equal to the current flowing through it multiplied by its resistance. Understanding this relationship is crucial for analyzing and designing circuits.

Consider a series circuit with a 12V battery and two resistors of 4Ω and 6Ω. First, calculate the total resistance: R_total = R1 + R2 = 4Ω + 6Ω = 10Ω. Using Ohm's Law, we find the current: I = V / R_total = 12V / 10Ω = 1.2A. This current flows through both resistors, demonstrating how series circuits work.

In a parallel circuit with a 12V battery and two resistors of 4Ω and 6Ω, we first calculate the total resistance using the formula 1/R_total = 1/R1 + 1/R2. This gives us 1/R_total = 1/4 + 1/6, which simplifies to R_total = 2.4Ω. Now, using Ohm's Law, we find the total current: I = V / R_total = 12V / 2.4Ω = 5A. This current is divided between the two resistors.

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

Now, consider a parallel circuit with a 12V battery and two resistors of 8Ω and 4Ω. Calculate the total resistance using the parallel formula. Then, determine the current flowing through each resistor. Discuss how the current divides between the two paths.

For your independent practice, solve the following problems: 1) A series circuit with a 24V battery and resistors of 6Ω and 12Ω. Calculate the total resistance and current. 2) A parallel circuit with a 10V battery and resistors of 5Ω and 10Ω. Find the total resistance and the current through each resistor. Show all your calculations.

Design a simple circuit using a 9V battery, a switch, and two different resistors. Draw the circuit diagram and calculate the total resistance and current. Explain how you would test the circuit to ensure it works as intended.

• Volts
• Amperes
• Ohms
• Watts

Answer: Ohms

Resistance is measured in Ohms, which is the standard unit in electrical engineering.

• Only that component stops working
• The entire circuit is interrupted
• The current increases
• The voltage drops

Answer: The entire circuit is interrupted

In a series circuit, all components are connected in a single path, so if one fails, the current cannot flow.

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

Answer: V = I × R

Ohm's Law defines the relationship between voltage, current, and resistance.

Answer: A parallel circuit is a type of electrical circuit where components are connected across common points or junctions, allowing multiple paths for current to flow.

In a parallel circuit, if one component fails, current can still flow through other paths.

Answer: 3A

Using Ohm's Law (I = V / R), the current is 15V / 5Ω = 3A.

• It increases
• It decreases
• It stays the same
• It doubles

Answer: It decreases

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

Answer: 10Ω

In a series circuit, total resistance is the sum of individual resistances: 4Ω + 6Ω = 10Ω.