Technical Science - Term 1 - Week 9

An electrical circuit consists of various components that work together to allow the flow of electricity. The main components include a power source (like a battery), conductors (wires), resistors (which limit current), and switches (which control the flow). Each component has a specific role; for example, the power source provides the necessary voltage to push the current through the circuit.

There are two primary types of circuits: series and parallel. In a series circuit, components are connected end-to-end, meaning the current flows through each component sequentially. If one component fails, the entire circuit is interrupted. In contrast, a parallel circuit has multiple paths for current to flow. If one component fails, the other paths remain functional, allowing the circuit to continue operating.

Ohm's Law is a fundamental principle in electronics that relates voltage (V), current (I), and resistance (R) in a circuit. It is expressed by the formula V = I × R. This law allows us to calculate one of these values if the other two are known. Understanding Ohm's Law is crucial for analyzing and designing electrical circuits.

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, we can find the current (I) flowing through the circuit: I = V / R_total = 12V / 10Ω = 1.2A. This means that 1.2A flows through each component in the series circuit.

In a parallel circuit with a 12V battery and two resistors of 4Ω and 6Ω, the voltage across each resistor is the same (12V). The current through each resistor can be calculated using Ohm's Law. For the 4Ω resistor: I1 = V / R1 = 12V / 4Ω = 3A. For the 6Ω resistor: I2 = V / R2 = 12V / 6Ω = 2A. The total current (I_total) in the circuit is the sum of the currents: I_total = I1 + I2 = 3A + 2A = 5A.

Let's practice calculating the total resistance in a series circuit. You have three resistors: 5Ω, 10Ω, and 15Ω connected in series. What is the total resistance? To find the total resistance, simply add the resistances together: R_total = 5Ω + 10Ω + 15Ω = 30Ω. Now, if we connect this series circuit to a 24V battery, what is the current flowing through the circuit? Using Ohm's Law, I = V / R_total = 24V / 30Ω = 0.8A.

Now it's your turn to design a simple circuit. Create a circuit diagram that includes a 9V battery, two resistors (one 3Ω and one 6Ω), and a switch. Calculate the total resistance if the resistors are in series and then in parallel. Finally, determine the current flowing through the circuit in both configurations using Ohm's Law.

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

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
• The current increases
• The voltage drops

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 the resistance.

Answer: A parallel circuit is a type of electrical circuit where multiple components are connected across the same voltage source, allowing current to flow through multiple paths.

In a parallel circuit, each component has its own path to the power source, which means if one component fails, the others can still operate.

Answer: 2A

Using Ohm's Law, I = V / R = 24V / 12Ω = 2A.

• They have multiple paths for current
• The total resistance is less than the smallest resistor
• The current is the same through all components
• Voltage is divided among components

Answer: The current is the same through all components

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