Technical Science - Term 1 - Week 7

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 main components of a circuit include resistors, capacitors, inductors, and power sources like batteries. 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 the three variables if the other two are known. For example, if we know the voltage across a resistor and its resistance, we can determine the current flowing through it.

Consider a circuit with a resistor of 10 ohms connected to a 5-volt battery. To find the current flowing through the resistor, we apply Ohm's Law: I = V / R. Substituting the values, we get I = 5V / 10Ω = 0.5A. This means that a current of 0.5 amperes flows through the circuit.

In a series circuit, the total resistance is the sum of individual resistances. For example, if we have two resistors, R1 = 4Ω and R2 = 6Ω, the total resistance R_total = R1 + R2 = 4Ω + 6Ω = 10Ω. If connected to a 20V battery, the current can be calculated using Ohm's Law: I = V / R_total = 20V / 10Ω = 2A.

Let's work through a problem together. A circuit has a voltage of 12V and a resistor of 3Ω. What is the current flowing through the circuit? Using Ohm's Law, we calculate I = V / R = 12V / 3Ω = 4A. Discuss with your partner how changing the resistance would affect the current.

Look at the circuit diagram on the board. Identify the components: resistors, power source, and any switches. Discuss the function of each component in the circuit. How would removing one component affect the overall circuit operation?

Now, it's your turn to solve some problems. Calculate the current in a circuit with a voltage of 24V and a resistor of 8Ω. Next, analyze a series circuit with three resistors: 2Ω, 3Ω, and 5Ω connected to a 30V battery. What is the total resistance and the current flowing through the circuit? Write down your calculations and be prepared to share your answers with the class.

Design a simple circuit diagram that includes at least one power source and two resistors. Label each component and calculate the total resistance. Then, determine the current if the power source provides 15V. Present your circuit to the class and explain your calculations.

• 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 series circuit is a circuit where components are connected end-to-end, so the same current flows through each component.

In a series circuit, the total resistance increases as more resistors are added, affecting the overall current.

• It increases
• It decreases
• It remains the same
• It becomes zero

Answer: It decreases

According to Ohm's Law, if resistance increases while voltage is constant, current must decrease.

Answer: 2A

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

• 10Ω
• 5Ω
• 15Ω
• 1Ω

Answer: 10Ω

In a series circuit, total resistance is the sum of individual resistances: 3Ω + 5Ω + 2Ω = 10Ω.

Answer: The total current decreases.

Removing a branch in a parallel circuit reduces the total pathways for current, thus decreasing the total current.

• Resistor
• Capacitor
• Inductor
• Switch

Answer: Capacitor

A capacitor stores electrical energy in an electric field, while other components serve different functions.