Technical Science - Term 2 - Week 7

An electrical circuit is a closed loop that allows electric current to flow. It consists of various components such as resistors, capacitors, and power sources. Understanding how these components interact is crucial for analyzing and designing circuits. The basic elements include a power source (like a battery), conductive paths (wires), and load components (like bulbs or motors) that use the electrical energy.

Ohm's Law is a fundamental principle in electronics that relates voltage (V), current (I), and resistance (R) in a circuit. The law is expressed as 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. Understanding this relationship allows us to calculate unknown values in a circuit.

Consider a circuit with a voltage of 12 volts and a resistance of 4 ohms. To find the current, we can use Ohm's Law: I = V/R. Substituting the values, we get I = 12V / 4Ω = 3A. This means that a current of 3 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 = 3Ω and R2 = 5Ω, the total resistance R_total = R1 + R2 = 3Ω + 5Ω = 8Ω. If the circuit is powered by a 16V battery, we can find the current using Ohm's Law: I = V/R_total = 16V / 8Ω = 2A.

Let's work through a problem together. A circuit has a voltage of 24 volts and a resistance of 6 ohms. What is the current flowing through the circuit? Use Ohm's Law to find the answer. Remember, I = V/R. Substitute the values: I = 24V / 6Ω. What do you get?

Look at the diagram of a simple circuit provided. Identify the power source, resistors, and any other components. Discuss with your partner how each component affects the flow of electricity in the circuit. What happens if one component fails?

Now it's your turn! Solve the following problems on your own: 1) A circuit has a voltage of 30V and a resistance of 10Ω. Calculate the current. 2) In a series circuit with three resistors (2Ω, 3Ω, and 5Ω), what is the total resistance? 3) If the total current in a circuit is 4A and the resistance is 2Ω, what is the voltage?

Design a simple circuit using at least three components: a power source, a resistor, and a load (like a light bulb). Draw the circuit diagram and label each component. Calculate the total resistance and the current if the power source provides 12V.

• Voltage equals current times resistance.
• Current equals voltage times resistance.
• Resistance equals voltage divided by current.
• All of the above.

Answer: Voltage equals current times resistance.

Ohm's Law states that V = I × R, which means voltage is the product of current and resistance.

• It is the sum of all resistances.
• It is the product of all resistances.
• It is the average of all resistances.
• It is the maximum resistance.

Answer: It is the sum of all resistances.

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

Answer: Ohm

The unit of electrical resistance is named after Georg Simon Ohm, and it is measured in ohms (Ω).

• 2A
• 5A
• 10A
• 15A

Answer: 2A

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

Answer: A parallel circuit is one where the components are connected across common points or junctions, providing multiple paths for current to flow.

In a parallel circuit, each component has the same voltage across it, but the total current is the sum of the currents through each component.

• It increases.
• It decreases.
• It stays the same.
• It doubles.

Answer: It decreases.

Adding more resistors in parallel decreases the total resistance because there are more paths for current to flow.