Technical Science - Term 3 - Week 1

An electrical circuit consists of various components that work together to allow the flow of electric current. The primary components include resistors, capacitors, inductors, power sources (like batteries), and conductors (wires). Each component has a specific function; for example, resistors limit the flow of current, while capacitors store electrical energy.

Ohm's Law is a fundamental principle in electronics that states the relationship between voltage (V), current (I), and resistance (R) in a circuit. It can be expressed with the formula V = I × R. This law helps us understand how changing one of these variables affects the others, allowing for calculations that are crucial in circuit design and analysis.

In a series circuit, components are connected end-to-end, so the same current flows through all components. The total resistance is the sum of individual resistances. In contrast, parallel circuits have components connected across the same voltage source, allowing multiple paths for current. The total resistance in parallel circuits is found using the formula 1/R_total = 1/R1 + 1/R2 + ... + 1/Rn.

Consider a series circuit with three resistors: R1 = 4Ω, R2 = 6Ω, and R3 = 10Ω. To find the total resistance (R_total), we add the resistances: R_total = R1 + R2 + R3 = 4Ω + 6Ω + 10Ω = 20Ω. This total resistance affects the current flowing through the circuit when a voltage is applied.

If a circuit has a voltage of 12V and a resistance of 3Ω, we can find the current using Ohm's Law. Rearranging the formula gives us I = V/R. Thus, I = 12V / 3Ω = 4A. This means that a current of 4 amperes flows through the circuit.

Let's work through an example together. We have two resistors in parallel: R1 = 5Ω and R2 = 10Ω. To find the total resistance, we use the formula 1/R_total = 1/R1 + 1/R2. Substituting the values gives us 1/R_total = 1/5 + 1/10. Finding a common denominator, we get 1/R_total = 2/10 + 1/10 = 3/10. Therefore, R_total = 10/3Ω, or approximately 3.33Ω.

Now, it's your turn to practice. Calculate the total resistance in a series circuit with resistors of 2Ω, 3Ω, and 5Ω. Then, find the current if the voltage across the circuit is 15V. Additionally, analyze a parallel circuit with resistors of 4Ω and 12Ω and determine the total resistance.

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

Answer: V = I × R

Ohm's Law states that voltage equals current multiplied by resistance.

• It is less than the smallest resistor
• It is equal to the smallest resistor
• It is the sum of all resistances
• It is the average of the resistances

Answer: It is the sum of all resistances

In a series circuit, the total resistance is the sum of all individual resistances.

• Current stops flowing
• Current increases
• Current decreases
• Current remains the same

Answer: Current remains the same

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

Answer: A resistor is a component that limits the flow of electric current in a circuit.

Resistors are used to control the amount of current that flows through a circuit, protecting other components.

Answer: 4A

Using Ohm's Law (I = V/R), we calculate I = 24V / 6Ω = 4A.

• 2Ω
• 3.2Ω
• 12Ω
• 32Ω

Answer: 3.2Ω

Using the formula 1/R_total = 1/R1 + 1/R2, we find R_total = 3.2Ω.

Answer: In series circuits, components are connected end-to-end, while in parallel circuits, components are connected across the same voltage source.