Technical Science - Term 2 - Week 3

An electrical circuit is a closed loop that allows current to flow. It consists of various components such as resistors, capacitors, and power sources. Understanding these components is crucial for analyzing how circuits function. The flow of electricity is driven by voltage, which is the potential difference between two points in a circuit.

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 are distributed within the circuit.

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 values if the other two are known, making it essential for circuit analysis and design.

Consider a simple series circuit with a 12V battery and two resistors of 4Ω and 6Ω. The total resistance (R_total) is the sum of the resistances: R_total = 4Ω + 6Ω = 10Ω. Using Ohm's Law, we can find the current (I) flowing through the circuit: I = V / R_total = 12V / 10Ω = 1.2A. Therefore, the same current flows through both resistors.

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 = 5/12, leading to R_total = 12/5 = 2.4Ω. The current can be calculated as I = V / R_total = 12V / 2.4Ω = 5A, indicating that the total current is divided among the branches.

Let's work through a problem together. We have a series circuit with a 9V battery and three resistors: 2Ω, 3Ω, and 5Ω. First, calculate the total resistance: R_total = 2Ω + 3Ω + 5Ω = 10Ω. Now, apply Ohm's Law to find the current: I = V / R_total = 9V / 10Ω. What is the current flowing through the circuit?

Now it's your turn! Solve the following problems: 1) A circuit has a 15V battery and two resistors in series: 3Ω and 7Ω. Calculate the current. 2) A parallel circuit has a 10V battery and two resistors: 5Ω and 10Ω. Find the total current flowing from the battery. Show all your calculations.

• Volts
• Amperes
• Ohms
• Watts

Answer: Ohms

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

• The same through all components
• Different in each component
• Zero
• Only flows through one component

Answer: The same through all components

In a series circuit, the same current flows through each component because they are connected end-to-end.

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

Answer: V = I × R

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

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

In a parallel circuit, each component receives the same voltage, and the total current is the sum of the currents through each branch.

• It doubles
• It halves
• It stays the same
• It quadruples

Answer: It halves

According to Ohm's Law, if resistance increases while voltage remains constant, the current will decrease.

Answer: 10Ω

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

• Resistor
• Capacitor
• Inductor
• Transistor