Technical Science - Term 1 - Week 10

An electrical circuit is a closed loop that allows electric current to flow. The basic components of a circuit include a power source (like a battery), conductors (wires), and loads (devices that use electricity, such as bulbs or motors). Understanding how these components work together is essential 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 parts. 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 continue functioning.

Ohm's Law is a fundamental principle in electronics that relates voltage (V), current (I), and resistance (R) in a circuit. It is expressed with the formula V = I × R. This law allows us to calculate any one of the three variables if the other two are known, making it a powerful tool for circuit analysis.

Consider a simple series circuit with a 9V battery and two resistors of 3Ω and 6Ω. To find the total resistance (R_total), we add the resistances: R_total = 3Ω + 6Ω = 9Ω. Using Ohm's Law, we can find the current (I) flowing through the circuit: I = V / R_total = 9V / 9Ω = 1A. Thus, the current flowing through the circuit is 1 ampere.

In a parallel circuit with a 12V battery and two resistors of 4Ω and 12Ω, we first find the total resistance using the formula 1/R_total = 1/R1 + 1/R2. This gives us 1/R_total = 1/4 + 1/12. Finding a common denominator, we get 1/R_total = 3/12 + 1/12 = 4/12, so R_total = 3Ω. The current through the circuit can then be calculated: I_total = V / R_total = 12V / 3Ω = 4A.

Let's work through a problem together. We have a series circuit with a 10V battery and two resistors of 2Ω and 3Ω. First, calculate the total resistance: R_total = 2Ω + 3Ω = 5Ω. Now, apply Ohm's Law to find the current: I = V / R_total = 10V / 5Ω. What is the current flowing through the circuit? (Answer: 2A)

Now, consider a parallel circuit with a 24V battery and two resistors of 6Ω and 3Ω. First, calculate the total resistance: 1/R_total = 1/6 + 1/3. Solve for R_total, then use Ohm's Law to find the current through each resistor. What is the voltage across each resistor? (Answer: 24V, since voltage is the same across all components in parallel.)

Now it's your turn to practice. Solve the following problems: 1) A series circuit has a 15V battery and two resistors of 5Ω and 10Ω. Calculate the current flowing through the circuit. 2) A parallel circuit has a 9V battery and two resistors of 3Ω and 6Ω. Calculate the total current flowing from the battery. Show your calculations and reasoning.

Design a simple circuit using at least one battery and two resistors. Specify whether it is a series or parallel circuit. Calculate the total resistance, current, and voltage across each component. Be prepared to present your circuit design and calculations to the class.

• Ohm
• Volt
• Ampere
• Watt

Answer: Ohm

Resistance is measured in Ohms, which is the standard unit in electrical engineering.

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

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 = R / I
• V = I - R

Answer: V = I × R

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

Answer: A parallel circuit has multiple paths for current to flow, allowing components to operate independently.

In a parallel circuit, if one component fails, the others can still function because there are alternative paths for current.

• It increases
• It decreases
• It remains the same
• It doubles

Answer: It decreases

Adding more resistors in parallel provides additional paths for current, reducing total resistance.

Answer: 3A

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

• 2Ω
• 10Ω
• 24Ω
• 0.67Ω

Answer: 10Ω

In a series circuit, total resistance is the sum of individual resistances: 4Ω + 6Ω = 10Ω.