Technical Science - Term 1 - Week 6

An electrical circuit is a closed loop that allows electric current to flow. The basic components of a circuit include a power source (like a battery), conductors (wires), and load devices (like resistors or light bulbs). Understanding how these components interact is crucial for analyzing and designing circuits.

Ohm's Law is a fundamental principle in electronics that states the relationship between voltage (V), current (I), and resistance (R) in a circuit. It can be expressed with the formula V = I × R. This law allows us to calculate one of the three variables if the other two are known, making it essential for circuit analysis.

Circuits can be classified as series or parallel. In a series circuit, components are connected end-to-end, and the same current flows through all components. In contrast, a parallel circuit has multiple paths for current to flow, meaning the voltage across each component is the same. Understanding these configurations helps in predicting how circuits behave under different conditions.

Consider a circuit with a voltage of 12 volts and a resistor of 4 ohms. To find the current, we apply Ohm's Law: I = V / R = 12V / 4Ω = 3A. This means that the current flowing through the circuit is 3 amperes.

If we have two resistors in series, one of 6 ohms and another of 4 ohms, the total resistance (R_total) is the sum of the individual resistances: R_total = R1 + R2 = 6Ω + 4Ω = 10Ω. This total resistance affects the current flowing through the circuit.

For two resistors in parallel, the total resistance can be calculated using the formula 1/R_total = 1/R1 + 1/R2. If R1 is 6 ohms and R2 is 3 ohms, then 1/R_total = 1/6 + 1/3 = 1/6 + 2/6 = 3/6. Thus, R_total = 2 ohms.

Let's analyze a circuit together. Given a circuit with a 9V battery and two resistors in series (3Ω and 6Ω), calculate the total resistance and the current flowing through the circuit. First, find the total resistance: R_total = 3Ω + 6Ω = 9Ω. Then, apply Ohm's Law: I = V / R_total = 9V / 9Ω = 1A. The current flowing through the circuit is 1 ampere.

In groups, create a simple circuit using resistors and a battery. Measure the voltage across each resistor and the total current flowing through the circuit. Discuss how the configuration (series or parallel) affects the measurements and share your findings with the class.

Complete the following problems for homework: 1) A circuit has a 15V battery and a resistor of 5Ω. Calculate the current. 2) Two resistors of 4Ω and 8Ω are in series. Find the total resistance. 3) For the same resistors in parallel, calculate the total resistance. Show all your workings.

Research different types of circuit components (like capacitors, inductors, and diodes) and their functions in electrical circuits. Prepare a short presentation to share with the class next week.

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

Answer: V = I × R

Ohm's Law states that voltage equals current multiplied by resistance.

• The same through all components
• Different for each component
• Zero
• Only flows through the first component

Answer: The same through all components

In a series circuit, the same current flows through each component.

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

Answer: It decreases

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

Answer: 3A

Using Ohm's Law, I = V / R = 24V / 8Ω = 3A.

Answer: 15Ω

In series, total resistance is the sum: R_total = 5Ω + 10Ω = 15Ω.

• Resistor
• Capacitor
• Inductor
• Transistor

Answer: Capacitor

A capacitor stores electrical energy in an electric field.

Answer: In series circuits, components are connected end-to-end, and the same current flows through all. In parallel circuits, components are connected across common points, allowing multiple paths for current.

This distinction affects how voltage and current are distributed in the circuit.