Technical Science - Term 4 - Week 5

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 electricity, while loads convert electrical energy into other forms of energy, such as light or heat.

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 broken. 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 electrical engineering that relates voltage (V), current (I), and resistance (R) in a circuit. It is expressed as V = I × R. This means that the voltage across a conductor is directly proportional to the current flowing through it, with resistance being the constant of proportionality. Understanding this relationship is crucial for analyzing and designing electrical circuits.

Consider a simple series circuit with a 9V battery and two resistors of 3Ω and 6Ω. To find the total resistance, we add the resistances: R_total = R1 + R2 = 3Ω + 6Ω = 9Ω. Using Ohm's Law, we can find the current: I = V / R_total = 9V / 9Ω = 1A. Thus, the current flowing through the circuit is 1 ampere.

In a parallel circuit with a 12V battery and two resistors of 4Ω and 12Ω, we first find the total resistance using the formula 1/R_total = 1/R1 + 1/R2. This gives us 1/R_total = 1/4 + 1/12, which simplifies to R_total = 3Ω. Now, applying Ohm's Law, the total current is I = V / R_total = 12V / 3Ω = 4A. The current splits between the two resistors based on their resistance values.

Let's work through a problem together. We have a series circuit with a 15V battery and two resistors of 5Ω and 10Ω. First, calculate the total resistance: R_total = 5Ω + 10Ω = 15Ω. Now, apply Ohm's Law to find the current: I = V / R_total. What is the current flowing through the circuit?

Now it's your turn! Solve the following problems independently: 1) A circuit has a 24V battery and two resistors in series (8Ω and 16Ω). Calculate the total current. 2) A parallel circuit has a 10V battery and two resistors (5Ω and 10Ω). Find the total current flowing from the battery. Show your calculations clearly.

• 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 breaks
• It increases current
• It decreases voltage

Answer: It breaks

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

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

Answer: V = I × R

Ohm's Law states that voltage (V) is equal to the product of current (I) and resistance (R).

• Same current through all components
• Voltage is the same across all components
• Total resistance is the sum of individual resistances
• One failure breaks the entire circuit

Answer: Voltage is the same across all components

In a parallel circuit, the voltage across each component is the same, while the current can vary.

Answer: A load is a component that consumes electrical energy, such as a light bulb or motor.

Loads convert electrical energy into other forms, like light or motion, and are essential for the functioning of a circuit.

Answer: The total resistance increases.

In a series circuit, the total resistance is the sum of all individual resistances, so adding more resistors increases the total.