Technical Science - Term 2 - Week 8

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 operate. 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 all components. In contrast, a parallel circuit has components connected across the same voltage source, allowing multiple paths for current to flow. This distinction affects how voltage and current are distributed in 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 the three variables if the other two are known, making it essential for circuit analysis.

Consider a 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, the current (I) can be calculated as I = V/R_total = 12V/10Ω = 1.2A. This current flows through both resistors.

In a parallel circuit with a 12V battery and two resistors of 4Ω and 6Ω, the total resistance (R_total) 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 through each resistor can then be 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 5Ω. First, calculate the total resistance: R_total = 3Ω + 5Ω = 8Ω. Now, apply Ohm's Law to find the current: I = V/R_total = 9V/8Ω. What is the current flowing through the circuit?

Now, let's analyze a parallel circuit with a 12V battery and two resistors of 2Ω and 3Ω. Calculate the total resistance using the formula for parallel circuits. After finding R_total, use Ohm's Law to determine the current flowing through each resistor. Discuss your findings with a partner.

Complete the following problems independently: 1) A series circuit has a 10V battery and two resistors of 2Ω and 8Ω. Calculate the current flowing through the circuit. 2) A parallel circuit has a 24V battery and two resistors of 4Ω and 12Ω. Find the total current supplied by the battery. Show all calculations.

Research a real-world application of electrical circuits, such as in household wiring or electronic devices. Write a short paragraph explaining how the principles of series and parallel circuits apply to your chosen example.

• 5Ω
• 10Ω
• 15Ω
• 50Ω

Answer: 15Ω

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

• Current is the same through all components.
• Voltage is the same across all components.
• Total resistance is the sum of all resistances.
• All components must be identical.

Answer: Voltage is the same across all components.

In parallel circuits, the voltage across each component is equal to the source voltage.

Answer: V = I × R

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

• 4A
• 5A
• 15A
• 20A

Answer: 4A

Using Ohm's Law, I = V/R = 20V/5Ω = 4A.

Answer: The total resistance decreases.

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

• The circuit remains functional.
• The circuit is broken.
• Only the failed component stops working.
• The current doubles.

Answer: The circuit is broken.

In a series circuit, if one component fails, it interrupts the flow of current, breaking the circuit.

• Volt
• Ampere
• Ohm
• Watt

Answer: Ohm

The unit of electrical resistance is the Ohm, symbolized by the Greek letter Omega (Ω).