Technical Science - Term 2 - Week 3

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 a power source (like a battery), conductors (wires), resistors, and sometimes switches. 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. The law states that V = I × R. This means that the voltage across a conductor is directly proportional to the current flowing through it, provided the temperature remains constant. This relationship allows us to calculate one of the three variables if the other two are known.

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

To draw a simple circuit diagram, start by representing the power source with a battery symbol. Connect wires using straight lines, and add a resistor symbol in the circuit path. For example, if we have a battery connected to a resistor, the diagram would show the battery symbol connected by lines to the resistor symbol, indicating the flow of current.

Let's work through a problem together. If a circuit has a voltage of 24 volts and a resistance of 6 ohms, what is the current? Use Ohm's Law: I = V / R. Substitute the values: I = 24V / 6Ω. Calculate the current and share your answer with the class.

Now, let's create a circuit diagram as a class. Imagine a circuit with a 9V battery and two resistors in series, one 3 ohms and the other 6 ohms. Draw the battery and connect it to the resistors in series. Label each component clearly. Discuss the importance of clarity in circuit diagrams.

For your independent practice, solve the following problems: 1) A circuit has a voltage of 15 volts and a resistance of 5 ohms. Calculate the current. 2) Draw a circuit diagram for a circuit with a 12V battery and a 10-ohm resistor. 3) If the current in a circuit is 2A and the resistance is 4 ohms, what is the voltage?

Research different types of circuit components (like capacitors, inductors, and diodes) and their functions. Prepare a short presentation to share with the class next week. Focus on how each component affects the overall circuit behavior.

• 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.

Answer: An electrical circuit is a closed loop that allows current to flow from a power source through various components and back to the source.

This definition captures the essential function of a circuit.

• 5A
• 2A
• 10A
• 20A

Answer: 5A

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

Answer: Power source, conductors, and load (or resistors).

These components are essential for the functioning of any electrical circuit.

• A straight line
• A zigzag line
• Two parallel lines
• A rectangle

Answer: Two parallel lines

In circuit diagrams, a battery is typically represented by two parallel lines, one longer than the other.

Answer: A resistor limits the flow of current in a circuit.

Resistors are used to control the amount of current that flows through a circuit.

• Increases
• Decreases
• Stays the same
• Becomes zero

Answer: Decreases

According to Ohm's Law, if resistance increases, current decreases when voltage is constant.