Technical Science - Term 4 - Week 2

An electrical circuit is a closed loop that allows current to flow from a power source through various components and back to the source. The basic components of a circuit include a power source (like a battery), conductors (wires), and load devices (like bulbs or resistors). Understanding how these components interact is crucial for analyzing and designing circuits.

Ohm's Law is a fundamental principle in electronics that relates voltage (V), current (I), and resistance (R) in a circuit. It is expressed as V = I × R. This law allows us to calculate one of these values if the other two are known. For example, if a circuit has a voltage of 12 volts and a resistance of 4 ohms, the current can be calculated as I = V/R = 12V/4Ω = 3A.

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, in a parallel circuit, components are connected across the same voltage source, allowing multiple paths for current. The total resistance in a parallel circuit is less than the smallest individual resistance, calculated using the formula 1/R_total = 1/R1 + 1/R2 + ... + 1/Rn.

Consider a circuit with a voltage of 24 volts and a resistance of 6 ohms. To find the current, we use Ohm's Law: I = V/R. Substituting the values, we get I = 24V/6Ω = 4A. This means that 4 amperes of current flow through the circuit.

If we have three resistors in series with values of 2Ω, 3Ω, and 5Ω, the total resistance can be calculated as R_total = R1 + R2 + R3 = 2Ω + 3Ω + 5Ω = 10Ω. This total resistance affects the current flowing through the circuit when a voltage is applied.

For two resistors in parallel, one with 4Ω and another with 6Ω, we can find the total resistance using the formula 1/R_total = 1/R1 + 1/R2. Thus, 1/R_total = 1/4 + 1/6. Finding a common denominator, we get 1/R_total = 3/12 + 2/12 = 5/12. Therefore, R_total = 12/5 = 2.4Ω.

Given a circuit with a voltage of 30 volts and a resistance of 10 ohms, calculate the current flowing through the circuit. Students should apply Ohm's Law (I = V/R) to find the answer. The expected answer is I = 30V/10Ω = 3A.

Students will work in pairs to calculate the total resistance of a series circuit containing resistors of 5Ω, 10Ω, and 15Ω. They should add the resistances together to find R_total = 5Ω + 10Ω + 15Ω = 30Ω.

In groups, students will analyze a parallel circuit with three resistors: 3Ω, 6Ω, and 12Ω. They will use the parallel resistance formula to find the total resistance. The expected result is R_total = 1/(1/3 + 1/6 + 1/12) = 1.5Ω.

Students will solve the following problem independently: A circuit has a voltage of 48 volts and a resistance of 12 ohms. Calculate the current. The answer should be I = 48V/12Ω = 4A.

Calculate the total resistance of a series circuit with resistors of 8Ω, 4Ω, and 2Ω. Students should find R_total = 8Ω + 4Ω + 2Ω = 14Ω.

Determine the total resistance of a parallel circuit with resistors of 5Ω and 10Ω. Students should calculate R_total using the formula 1/R_total = 1/5 + 1/10, leading to R_total = 3.33Ω.

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

Answer: V = I × R

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

• The sum of all resistances
• The average of all resistances
• The product of all resistances
• The smallest resistance

Answer: The sum of all resistances

In a series circuit, the total resistance is simply the sum of each individual resistance.

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

Answer: It decreases

Adding more branches in a parallel circuit provides additional paths for current, thus reducing total resistance.

Answer: 4A

Using Ohm's Law, I = V/R = 60V/15Ω = 4A.

Answer: 35Ω

In series, total resistance is R_total = 5Ω + 10Ω + 20Ω = 35Ω.

• Resistor
• Capacitor
• Inductor
• Transistor

Answer: None of the above

All listed components can be found in various electrical circuits.

Answer: 10V

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