Technical Science - Term 1 - Week 4

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

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 all components. In contrast, a parallel circuit has multiple paths for current to flow, meaning that the voltage across each component is the same. Each type has its own advantages and applications in real-world scenarios.

Ohm's Law is a fundamental principle in electronics that relates voltage (V), current (I), and resistance (R) in a circuit. The law states that V = I × R. This means that the voltage across a conductor is directly proportional to the current flowing through it, provided the temperature remains constant. Understanding this relationship is essential for circuit analysis.

Consider a series circuit with a 12V battery and two resistors of 4Ω and 6Ω. To find the total resistance (R_total), we add 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. This 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, which gives R_total = 12/5 = 2.4Ω. The current through the circuit can then be calculated as I = V / R_total = 12V / 2.4Ω = 5A.

Let's work through a problem together. You 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, consider a parallel circuit with a 12V battery and two resistors of 2Ω and 3Ω. Calculate the total resistance using the parallel formula. After finding R_total, determine the current flowing through each resistor. Remember to use the voltage across each resistor, which remains constant at 12V.

For independent practice, solve the following problems: 1) A series circuit with a 10V battery and two resistors of 2Ω and 3Ω. Calculate the total resistance and current. 2) A parallel circuit with a 24V battery and two resistors of 4Ω and 12Ω. Find the total resistance and the current through each resistor. Show all your calculations.

Think about how electrical circuits are used in everyday devices. Choose a device, such as a flashlight or a toaster, and describe the type of circuit it uses. Explain how the components work together to perform the device's function. Be prepared to share your findings with the class.

• To store electrical energy
• To limit current flow
• To increase voltage
• To convert AC to DC

Answer: To limit current flow

Resistors are used in circuits to limit the amount of current that can flow, protecting components from damage.

• Only that component stops working
• The entire circuit stops working
• The current increases
• The voltage doubles

Answer: The entire circuit stops working

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

Answer: V = I × R

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

• 2.4Ω
• 10Ω
• 24Ω
• 1.5Ω

Answer: 2.4Ω

The total resistance in a parallel circuit is calculated using the formula 1/R_total = 1/R1 + 1/R2.

Answer: The voltage remains the same across all components.

In a parallel circuit, each component experiences the same voltage as the power source.

• 3A
• 12A
• 48A
• 0.33A

Answer: 3A

Using Ohm's Law, I = V / R = 12V / 4Ω = 3A.

Answer: In a series circuit, components are connected end-to-end, while in a parallel circuit, components are connected across common points, allowing multiple paths for current.