ISCET Electronic Components & Circuit Analysis — Questions and Answers

Question 1: What is the function of a capacitor in an electronic circuit?

To amplify signals
To generate electricity
To store and release electrical energy (Correct answer)
To block current completely

Correct answer: To store and release electrical energy

A capacitor is a passive electronic component designed to store electrical energy in an electric field. It consists of two conductive plates separated by a dielectric material. This stored energy can then be released back into the circuit, making capacitors essential for filtering, timing, and energy storage applications in various electronic circuits.

Question 2: What happens when a diode is forward biased?

It blocks all current
It acts like a resistor
It allows current to flow (Correct answer)
It stores charge

Correct answer: It allows current to flow

A diode is a semiconductor device that acts as a one-way valve for electric current. When a diode is forward biased, meaning the voltage applied across it is in the correct direction (positive to anode, negative to cathode), it allows current to flow through it with minimal resistance. Conversely, it blocks current when reverse biased.

Question 3: What is Ohm’s Law?

V = I/R
V = IR (Correct answer)
V = R/I
V = I + R

Correct answer: V = IR

Ohm's Law is a fundamental principle in electronics that describes the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit. The formula V = IR states that the voltage across a conductor is directly proportional to the current flowing through it, given a constant resistance. This law is crucial for analyzing and designing circuits.

Question 4: Which component is used to resist current in a circuit?

Inductor
Transistor
Resistor (Correct answer)
Capacitor

Correct answer: Resistor

A resistor is a passive two-terminal electrical component specifically designed to oppose or limit the flow of electric current in a circuit. It introduces electrical resistance, which converts some electrical energy into heat. Resistors are used to control current levels, divide voltage, and protect other components from excessive current.

Question 5: What is the unit of electrical resistance?

Ampere
Volt
Ohm (Correct answer)
Watt

Correct answer: Ohm

The Ohm (symbol Ω) is the SI derived unit of electrical resistance, named after German physicist Georg Simon Ohm. It quantifies how much a material or component opposes the flow of electric current. One Ohm is defined as the resistance between two points of a conductor when a constant potential difference of one volt, applied to these points, produces a current of one ampere.

Question 6: Which device is used to control current in a circuit?

Resistor
Transistor (Correct answer)
Diode
Capacitor

Correct answer: Transistor

A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It can act as an electronic switch, allowing or blocking current flow based on a small input signal applied to its control terminal. This ability to control larger currents with smaller ones makes transistors fundamental components in modern electronics, from microprocessors to amplifiers.

Question 7: How is total resistance calculated in a series circuit?

Multiply all resistances
Divide largest by smallest
Subtract the smallest from the largest
Add all resistances (Correct answer)

Correct answer: Add all resistances

In a series circuit, components are connected end-to-end, creating a single path for the current to flow. To calculate the total resistance of resistors connected in series, you simply add the individual resistance values together. This is because each resistor contributes to the overall opposition to current flow along that single path.

Question 8: Which of the following components is polarized?

Resistor
Inductor
Electrolytic Capacitor (Correct answer)
Transformer

Correct answer: Electrolytic Capacitor

A polarized component is one that must be connected in a specific orientation with respect to the voltage polarity in a circuit to function correctly and avoid damage. Electrolytic capacitors are a common example of polarized components, having distinct positive and negative terminals. Connecting them incorrectly can lead to malfunction or even explosion.

Question 9: What is the main function of an inductor in a circuit?

To convert AC to DC
To regulate voltage
To store energy in a magnetic field (Correct answer)
To amplify signals

Correct answer: To store energy in a magnetic field

An inductor is a passive electrical component that stores energy in a magnetic field when electric current flows through it, typically consisting of a coil of wire. Its main function is to oppose changes in current flow. Inductors are used in circuits for filtering, tuning, and energy storage applications, particularly in AC circuits.

ISCET Electronic Components & Circuit Analysis

What is the function of a capacitor in an electronic circuit?