Technical Science - Term 4 - Week 3

An electrical circuit consists of several key components: a power source (like a battery), conductors (wires), and loads (devices that use electricity, such as bulbs or motors). The power source provides the necessary voltage to push the current through the circuit. Conductors allow the flow of electricity, while loads convert electrical energy into other forms of energy, such as light or motion.

Circuits can be classified into two main types: series and parallel. In a series circuit, components are connected end-to-end, so the same current flows through each component. If one component fails, the entire circuit stops working. 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 remain operational.

Ohm's Law is a fundamental principle in electrical engineering, defined by the equation V = I × R, where V is voltage, I is current, and R is resistance. This law allows us to calculate the relationship between these three quantities. Understanding Ohm's Law is essential for analyzing circuits and solving problems related to electrical systems.

Suppose we have a circuit with a voltage of 12 volts and a current of 3 amperes. To find the resistance, we can rearrange Ohm's Law: R = V / I. Plugging in the values, we get R = 12V / 3A = 4 ohms. This means the resistance in the circuit is 4 ohms.

Consider a series circuit with two resistors: R1 = 2 ohms and R2 = 3 ohms. The total resistance in a series circuit is the sum of the individual resistances: R_total = R1 + R2 = 2Ω + 3Ω = 5Ω. If the circuit is powered by a 10V battery, the current can be calculated using Ohm's Law: I = V / R_total = 10V / 5Ω = 2A.

Let's analyze a parallel circuit with two resistors: R1 = 6 ohms and R2 = 3 ohms. The total resistance in a parallel circuit can be calculated using the formula 1/R_total = 1/R1 + 1/R2. First, we find the reciprocal of each resistor: 1/6 + 1/3 = 1/6 + 2/6 = 3/6. Therefore, R_total = 6/3 = 2 ohms. Now, if we apply a voltage of 12V across this circuit, what is the total current flowing through the circuit?

Now it's your turn to solve some problems. Calculate the total resistance in a series circuit with three resistors: R1 = 4 ohms, R2 = 5 ohms, and R3 = 6 ohms. Then, using a voltage of 24V, determine the current flowing through the circuit. Additionally, analyze a parallel circuit with R1 = 8 ohms and R2 = 4 ohms, and find the total resistance and current if the voltage is 12V.

• Volts
• Amperes
• Ohms
• Watts

Answer: Ohms

Resistance is measured in ohms, which quantifies how much a material opposes the flow of electric current.

• It continues to work
• It stops working
• The current increases
• The voltage decreases

Answer: It stops working

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

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

Answer: V = I × R

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

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, if one component fails, current can still flow through other paths, keeping the circuit operational.

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

Answer: It decreases

Adding more resistors in parallel provides additional paths for current, which reduces the overall resistance.

Answer: 2A

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

• Resistor
• Capacitor
• Inductor
• Transistor