Technical Science - Term 2 - Week 7

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 electrons through the circuit. Conductors allow the flow of electric current, 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, 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, allowing the circuit to remain operational.

Ohm's Law is a fundamental principle in electronics that relates voltage (V), current (I), and resistance (R) in a circuit. It is expressed by the formula V = I × R. This law allows us to calculate the missing value when two of the three quantities are known. Understanding Ohm's Law is essential for analyzing and designing electrical 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, the total 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 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 gives R_total = 2.4Ω. The total current from the battery can then be calculated as I = V / R_total = 12V / 2.4Ω = 5A. Each resistor will have a different current flowing through it, calculated using Ohm's Law.

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

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 using Ohm's Law. Let's discuss the steps together before you try it on your own.

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 your calculations clearly.

Think about a household circuit that powers multiple devices. Write a short paragraph explaining how understanding series and parallel circuits can help in troubleshooting electrical issues at home. Consider what happens if one device fails in each type of circuit.

• Volts
• Amperes
• Ohms
• Watts

Answer: Ohms

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

• It continues to work
• It stops working
• Only the failed component stops
• The voltage increases

Answer: It stops working

In a series circuit, all components are connected in a single path, so if one fails, the entire circuit is interrupted.

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

Answer: V = I × R

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

Answer: 15Ω

In a series circuit, total resistance is the sum of all resistances: 5Ω + 10Ω = 15Ω.

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

Answer: It increases

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

Answer: 5A

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

• Battery
• Resistor
• Transistor
• Magnet

Answer: Magnet

While magnets can interact with electric circuits, they are not standard components of an electrical circuit.