Technical Science - Term 3 - Week 5

An electrical circuit is a closed loop that allows current to flow. The main components include a power source (like a battery), conductors (wires), and load devices (like bulbs or resistors). Each component plays a crucial role in ensuring the circuit functions correctly. The power source provides the energy, conductors allow the flow of electricity, and loads convert electrical energy into other forms, 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 all components. If one component fails, the entire circuit is interrupted. 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 continue functioning.

Ohm's Law is a fundamental principle in electronics that relates voltage (V), current (I), and resistance (R) in a circuit. It 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 Ohm's Law is essential for analyzing and designing electrical circuits.

Consider a series circuit with a 12V battery and two resistors: R1 = 4Ω and R2 = 6Ω. The total resistance (R_total) is R1 + R2 = 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: R1 = 4Ω and R2 = 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, which simplifies to R_total = 2.4Ω. The current through each resistor can be calculated using Ohm's Law, showing that different currents flow through each path.

Let's work together on a problem. We have a series circuit with a 9V battery and two resistors: R1 = 3Ω and R2 = 3Ω. First, calculate the total resistance: R_total = R1 + R2 = 3Ω + 3Ω = 6Ω. Now, apply Ohm's Law to find the current: I = V/R_total = 9V/6Ω. What is the current flowing through the circuit?

Now, let's analyze a parallel circuit with a 12V battery and two resistors: R1 = 6Ω and R2 = 3Ω. Calculate the total resistance using the formula for parallel circuits. Then, determine the current flowing through each resistor. Remember to use Ohm's Law for each path!

For your independent practice, solve the following problems: 1) A series circuit has a 15V battery and two resistors: R1 = 5Ω and R2 = 10Ω. Calculate the total current. 2) A parallel circuit has a 24V battery and two resistors: R1 = 8Ω and R2 = 4Ω. Find the total current flowing from the battery. Show all your calculations and reasoning.

• To store energy
• To limit current
• To increase voltage
• To convert energy

Answer: To limit current

Resistors are used to limit the flow of electric current in a circuit.

• The circuit continues to function
• The circuit is interrupted
• Only the failed component stops working
• The voltage increases

Answer: The circuit is interrupted

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

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

Answer: V = I × R

Ohm's Law states that voltage is equal to the current multiplied by resistance.

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

In a parallel circuit, if one component fails, current can still flow through other paths.

Answer: 2A

Using Ohm's Law, I = V/R = 10V/5Ω = 2A.

• It decreases
• It increases
• It remains the same
• It becomes zero

Answer: It increases

Adding more resistors in series increases the total resistance of the circuit.

• Battery
• Resistor
• Capacitor
• Magnet