Basic Electronics MCQs

What is Basic Electronics?

Master Basic Electronics with high-quality MCQs covering circuits, diodes, transistors, and more. Practice exam-focused questions with answers to boost your concepts and test performance.

The basic unit of an electronic circuit is:
- a) Resistor
- b) Capacitor
- c) Diode
- d) Transistor
  Answer: a) Resistor
A semiconductor device that allows current to flow in one direction only is:
- a) Capacitor
- b) Diode
- c) Inductor
- d) Transistor
  Answer: b) Diode
The unit of capacitance is:
- a) Ohm
- b) Farad
- c) Henry
- d) Tesla
  Answer: b) Farad
The device used to store electrical energy in an electric field is:
- a) Resistor
- b) Capacitor
- c) Inductor
- d) Diode
  Answer: b) Capacitor
In a transistor, the region between the collector and the base is called the:
- a) Emitter
- b) Base
- c) Collector
- d) Junction
  Answer: d) Junction
The component that opposes the flow of electric current is:
- a) Capacitor
- b) Inductor
- c) Resistor
- d) Diode
  Answer: c) Resistor
A device that can amplify electronic signals is:
- a) Diode
- b) Capacitor
- c) Transistor
- d) Resistor
  Answer: c) Transistor
In a P-N junction diode, the region where no charge carriers are present is called the:
- a) Forward bias
- b) Reverse bias
- c) Depletion region
- d) Conduction region
  Answer: c) Depletion region
The voltage across a diode in forward bias condition is approximately:
- a) 0.1 V
- b) 0.5 V
- c) 0.7 V
- d) 1.5 V
  Answer: c) 0.7 V
The primary function of a capacitor in a circuit is to:
- a) Store energy
- b) Amplify signals
- c) Regulate voltage
- d) Resist current
  Answer: a) Store energy
The unit of electrical resistance is:
- a) Ohm
- b) Farad
- c) Henry
- d) Tesla
  Answer: a) Ohm
The purpose of a transistor is to:
- a) Store electrical energy
- b) Resist the flow of current
- c) Amplify or switch electronic signals
- d) Store electrical charge
  Answer: c) Amplify or switch electronic signals
The component used to filter out unwanted frequencies from a signal is:
- a) Resistor
- b) Diode
- c) Capacitor
- d) Transistor
  Answer: c) Capacitor
The resistance of a conductor increases with:
- a) Increase in temperature
- b) Decrease in temperature
- c) Increase in voltage
- d) Increase in capacitance
  Answer: a) Increase in temperature
The polarity of a P-type semiconductor is:
- a) Positive
- b) Negative
- c) Neutral
- d) Variable
  Answer: a) Positive
The process of adding impurities to a semiconductor to change its electrical properties is called:
- a) Doping
- b) Conducting
- c) Polishing
- d) Soldering
  Answer: a) Doping
The purpose of a rectifier is to:
- a) Amplify signals
- b) Convert AC to DC
- c) Store electrical charge
- d) Regulate voltage
  Answer: b) Convert AC to DC
In a transistor, the middle region is called the:
- a) Emitter
- b) Base
- c) Collector
- d) Junction
  Answer: b) Base
An inductor’s primary function is to:
- a) Store energy in a magnetic field
- b) Amplify signals
- c) Store electrical energy
- d) Convert AC to DC
  Answer: a) Store energy in a magnetic field
The diode that emits light when current passes through it is called:
- a) Zener diode
- b) Light Emitting Diode (LED)
- c) Photodiode
- d) Schottky diode
  Answer: b) Light Emitting Diode (LED)
The resistance of a resistor is measured in:
- a) Volts
- b) Amperes
- c) Ohms
- d) Farads
  Answer: c) Ohms
The current flowing through a capacitor is:
- a) Directly proportional to the voltage
- b) Inversely proportional to the voltage
- c) Dependent on the frequency of the AC signal
- d) Always zero
  Answer: c) Dependent on the frequency of the AC signal
The output of a common emitter amplifier is taken from the:
- a) Emitter
- b) Base
- c) Collector
- d) Junction
  Answer: c) Collector
A device that allows current to flow in both directions but with different characteristics is:
- a) Diode
- b) Zener diode
- c) LED
- d) Transistor
  Answer: b) Zener diode
The primary function of a resistor in a circuit is to:
- a) Store energy
- b) Convert AC to DC
- c) Limit current
- d) Amplify signals
  Answer: c) Limit current
The symbol for a variable resistor is:
- a) A straight line with a zigzag
- b) A rectangle with an arrow
- c) A circle with an arrow
- d) A rectangle with a diagonal line
  Answer: c) A circle with an arrow
A diode in reverse bias condition will:
- a) Conduct current easily
- b) Block current flow
- c) Emit light
- d) Act as a variable resistor
  Answer: b) Block current flow
The property of a capacitor to resist changes in voltage is called:
- a) Capacitance
- b) Inductance
- c) Reactance
- d) Impedance
  Answer: c) Reactance
In a transistor, the current that flows from the emitter to the base is called:
- a) Base current
- b) Collector current
- c) Emitter current
- d) Leakage current
  Answer: a) Base current
The unit of inductance is:
- a) Ohm
- b) Farad
- c) Henry
- d) Tesla
  Answer: c) Henry
The characteristic curve of a diode shows the relationship between:
- a) Voltage and current
- b) Capacitance and resistance
- c) Inductance and frequency
- d) Power and voltage
  Answer: a) Voltage and current
The main purpose of a voltage divider circuit is to:
- a) Amplify signals
- b) Provide multiple output voltages
- c) Convert AC to DC
- d) Filter frequencies
  Answer: b) Provide multiple output voltages
The combination of resistors in series has:
- a) The same current through all resistors
- b) The same voltage across all resistors
- c) The total resistance equal to the sum of individual resistances
- d) A lower total resistance than any individual resistor
  Answer: c) The total resistance equal to the sum of individual resistances
The primary function of a transistor in a circuit is to:
- a) Store charge
- b) Control current flow
- c) Increase voltage
- d) Decrease capacitance
  Answer: b) Control current flow
The resistance of a conductor is affected by:
- a) Length and cross-sectional area
- b) Temperature and material
- c) Both a and b
- d) Voltage applied
  Answer: c) Both a and b
A transistor in common emitter configuration has its output taken from the:
- a) Emitter
- b) Collector
- c) Base
- d) Junction
  Answer: b) Collector
The process of removing the insulating layer from a wire to make an electrical connection is called:
- a) Soldering
- b) Stripping
- c) Doping
- d) Soldering
  Answer: b) Stripping
The function of a Zener diode is to:
- a) Emit light
- b) Amplify signals
- c) Regulate voltage
- d) Store energy
  Answer: c) Regulate voltage
The total capacitance of capacitors in series is:
- a) Equal to the sum of their individual capacitances
- b) The reciprocal of the sum of the reciprocals of their individual capacitances
- c) The same as the highest individual capacitance
- d) The same as the lowest individual capacitance
  Answer: b) The reciprocal of the sum of the reciprocals of their individual capacitances
In an AC circuit, the impedance of an inductor is:
- a) Directly proportional to the frequency of the AC signal
- b) Inversely proportional to the frequency of the AC signal
- c) Unaffected by the frequency of the AC signal
- d) Equal to the resistance of the inductor
  Answer: a) Directly proportional to the frequency of the AC signal
The unit of electric charge is:
- a) Volt
- b) Ampere
- c) Coulomb
- d) Ohm
  Answer: c) Coulomb
The characteristic of an ideal resistor is:
- a) Zero resistance
- b) Infinite resistance
- c) Resistance independent of temperature
- d) Resistance dependent on voltage
  Answer: c) Resistance independent of temperature
The frequency response of a capacitor is:
- a) Decreases with increasing frequency
- b) Increases with increasing frequency
- c) Constant with varying frequency
- d) Non-linear with frequency
  Answer: b) Increases with increasing frequency
A transistor in common base configuration has its input taken from the:
- a) Emitter
- b) Base
- c) Collector
- d) Junction
  Answer: a) Emitter
The process of connecting electronic components together to form a circuit is known as:
- a) Soldering
- b) Stripping
- c) Wiring
- d) Assembling
  Answer: a) Soldering
A capacitor in a DC circuit behaves as:
- a) A short circuit
- b) An open circuit
- c) A resistor
- d) A variable resistor
  Answer: b) An open circuit
The forward bias of a diode allows:
- a) Current to flow easily
- b) Current to be blocked
- c) The diode to be non-conductive
- d) The diode to reverse bias
  Answer: a) Current to flow easily
The property of a material that allows it to store electrical energy in an electric field is called:
- a) Capacitance
- b) Conductance
- c) Inductance
- d) Impedance
  Answer: a) Capacitance
The primary use of a diode in a circuit is:
- a) To store charge
- b) To regulate voltage
- c) To convert AC to DC
- d) To amplify signals
  Answer: c) To convert AC to DC
The voltage across a capacitor in an AC circuit is:
- a) In phase with the current
- b) Out of phase with the current
- c) Always zero
- d) Equal to the current
  Answer: b) Out of phase with the current
The resistance of a semiconductor increases with:
- a) Decreasing temperature
- b) Increasing temperature
- c) Decreasing voltage
- d) Increasing voltage
  Answer: a) Decreasing temperature
The total inductance of inductors in series is:
- a) The reciprocal of the sum of their individual inductances
- b) Equal to the sum of their individual inductances
- c) The same as the highest individual inductance
- d) The same as the lowest individual inductance
  Answer: b) Equal to the sum of their individual inductances
A transistor in common collector configuration has its input taken from the:
- a) Emitter
- b) Base
- c) Collector
- d) Junction
  Answer: b) Base
The resistance of a capacitor in an AC circuit is:
- a) Directly proportional to the frequency of the AC signal
- b) Inversely proportional to the frequency of the AC signal
- c) Constant with varying frequency
- d) Equal to the capacitance of the capacitor
  Answer: b) Inversely proportional to the frequency of the AC signal
The unit of electric power is:
- a) Volt
- b) Ampere
- c) Watt
- d) Ohm
  Answer: c) Watt
A component that can be used to adjust the level of a signal in a circuit is:
- a) Capacitor
- b) Resistor
- c) Transistor
- d) Diode
  Answer: b) Resistor
The term used to describe the opposition of a capacitor to a change in voltage is:
- a) Reactance
- b) Impedance
- c) Resistance
- d) Capacitance
  Answer: a) Reactance
The characteristic curve of an NPN transistor shows the relationship between:
- a) Voltage and base current
- b) Collector current and base current
- c) Collector current and emitter current
- d) Base current and emitter current
  Answer: b) Collector current and base current
The function of a rectifier circuit is to:
- a) Store electrical energy
- b) Filter signals
- c) Convert AC to DC
- d) Regulate voltage
  Answer: c) Convert AC to DC
A transistor used as a switch operates in the:
- a) Active region
- b) Cut-off region
- c) Saturation region
- d) Breakdown region
  Answer: c) Saturation region
The purpose of a transformer in an AC circuit is to:
- a) Amplify signals
- b) Convert DC to AC
- c) Change the voltage level
- d) Store electrical charge
  Answer: c) Change the voltage level
The output of a common base amplifier is taken from the:
- a) Base
- b) Emitter
- c) Collector
- d) Junction
  Answer: c) Collector
The property of an inductor to resist changes in current is called:
- a) Inductance
- b) Reactance
- c) Resistance
- d) Impedance
  Answer: a) Inductance
The frequency response of an inductor is:
- a) Decreases with increasing frequency
- b) Increases with increasing frequency
- c) Constant with varying frequency
- d) Non-linear with frequency
  Answer: b) Increases with increasing frequency
A semiconductor material that has more free electrons than holes is called:
- a) P-type
- b) N-type
- c) Insulator
- d) Conductor
  Answer: b) N-type
The unit of electric charge is:
- a) Ampere
- b) Volt
- c) Coulomb
- d) Ohm
  Answer: c) Coulomb
The purpose of an electrolytic capacitor is:
- a) To provide high capacitance in a small size
- b) To resist high-frequency signals
- c) To store large amounts of charge
- d) To amplify signals
  Answer: a) To provide high capacitance in a small size
In a transistor, the base current is:
- a) The same as the collector current
- b) The same as the emitter current
- c) A small fraction of the emitter current
- d) Equal to the total current
  Answer: c) A small fraction of the emitter current
The process of combining multiple resistors to achieve a specific resistance is called:
- a) Series connection
- b) Parallel connection
- c) Doping
- d) Filtering
  Answer: a) Series connection
The voltage drop across a diode in reverse bias is:
- a) Very small
- b) Zero
- c) Equal to the applied voltage
- d) Constant
  Answer: a) Very small
The purpose of a potentiometer in a circuit is to:
- a) Store electrical charge
- b) Vary resistance
- c) Regulate voltage
- d) Amplify signals
  Answer: b) Vary resistance
The internal resistance of a battery is:
- a) The resistance offered by the battery to the flow of current
- b) The resistance of the battery to the chemical reactions
- c) The resistance of the battery to external circuits
- d) The resistance to heat dissipation
  Answer: a) The resistance offered by the battery to the flow of current
The symbol for a capacitor is:
- a) A straight line with a zigzag
- b) Two parallel lines
- c) A circle with an arrow
- d) A rectangle with a diagonal line
  Answer: b) Two parallel lines
The property of a diode to emit light is utilized in:
- a) Photodiodes
- b) Zener diodes
- c) Light Emitting Diodes (LEDs)
- d) Schottky diodes
  Answer: c) Light Emitting Diodes (LEDs)
In a series RC circuit, the impedance is:
- a) Equal to the resistance of the resistor
- b) Equal to the reactance of the capacitor
- c) The sum of the resistance and capacitive reactance
- d) The reciprocal of the sum of resistance and capacitive reactance
  Answer: c) The sum of the resistance and capacitive reactance
The primary function of a rectifier in a power supply circuit is to:
- a) Filter AC signals
- b) Convert AC to DC
- c) Store electrical energy
- d) Amplify signals
  Answer: b) Convert AC to DC
The main characteristic of a common collector transistor configuration is:
- a) High current gain
- b) Voltage amplification
- c) High input impedance and low output impedance
- d) High voltage gain
  Answer: c) High input impedance and low output impedance
The process of a capacitor charging and discharging in an RC circuit is described by:
- a) Ohm’s Law
- b) Kirchhoff’s Law
- c) The exponential function
- d) The linear function
  Answer: c) The exponential function
The frequency response of a transistor amplifier is:
- a) A plot of current vs. voltage
- b) A plot of gain vs. frequency
- c) A plot of power vs. voltage
- d) A plot of resistance vs. current
  Answer: b) A plot of gain vs. frequency
In a common emitter amplifier, the input signal is applied to the:
- a) Emitter
- b) Collector
- c) Base
- d) Junction
  Answer: c) Base
The value of the forward resistance of a diode in forward bias is:
- a) Very high
- b) Zero
- c) Low
- d) Infinite
  Answer: c) Low
The property of a capacitor that determines how much charge it can store is:
- a) Capacitance
- b) Reactance
- c) Impedance
- d) Inductance
  Answer: a) Capacitance
The primary application of a variable resistor is:
- a) To amplify signals
- b) To adjust the level of current or voltage
- c) To store electrical charge
- d) To convert AC to DC
  Answer: b) To adjust the level of current or voltage
In an RC circuit, the time constant is given by:
- a) The product of resistance and capacitance
- b) The sum of resistance and capacitance
- c) The reciprocal of resistance
- d) The reciprocal of capacitance
  Answer: a) The product of resistance and capacitance
The property of an inductor to resist changes in current is known as:
- a) Inductance
- b) Reactance
- c) Resistance
- d) Impedance
  Answer: a) Inductance
The output voltage of a transformer is:
- a) Directly proportional to the primary voltage
- b) Inversely proportional to the number of turns in the secondary coil
- c) Dependent on the frequency of the AC signal
- d) The same as the input voltage
  Answer: a) Directly proportional to the primary voltage
The forward bias of a diode results in:
- a) Increased resistance
- b) Decreased resistance
- c) No current flow
- d) High reverse voltage
  Answer: b) Decreased resistance
In a common base amplifier, the input signal is applied to the:
- a) Collector
- b) Emitter
- c) Base
- d) Junction
  Answer: b) Emitter
The unit of electric power is:
- a) Watt
- b) Ohm
- c) Volt
- d) Ampere
  Answer: a) Watt
A resistor in parallel with a capacitor will:
- a) Increase the total resistance
- b) Decrease the total resistance
- c) Change the total capacitance
- d) Have no effect on the total capacitance
  Answer: b) Decrease the total resistance
The main purpose of an amplifier in a circuit is to:
- a) Increase the signal strength
- b) Store electrical energy
- c) Convert AC to DC
- d) Regulate voltage
  Answer: a) Increase the signal strength
In a series RC circuit, the impedance is:
- a) The sum of resistance and capacitive reactance
- b) The reciprocal of the sum of resistance and capacitive reactance
- c) The same as the resistance
- d) The same as the capacitive reactance
  Answer: a) The sum of resistance and capacitive reactance
The characteristic of a Zener diode is to:
- a) Emit light
- b) Regulate voltage
- c) Amplify signals
- d) Store energy
  Answer: b) Regulate voltage
The primary function of an amplifier is to:
- a) Increase signal power
- b) Decrease signal power
- c) Convert DC to AC
- d) Filter signals
  Answer: a) Increase signal power
The symbol for an inductor is:
- a) A rectangle with a zigzag
- b) A circle with a diagonal line
- c) A coil of wire
- d) A rectangle with a diagonal line
  Answer: c) A coil of wire
The total capacitance of capacitors in parallel is:
- a) Equal to the sum of their individual capacitances
- b) The reciprocal of the sum of the reciprocals of their individual capacitances
- c) The same as the highest individual capacitance
- d) The same as the lowest individual capacitance
  Answer: a) Equal to the sum of their individual capacitances
In a common emitter amplifier, the phase relationship between input and output signals is:
- a) In phase
- b) Out of phase
- c) No phase shift
- d) Depends on frequency
  Answer: b) Out of phase
The unit of electric charge is:
- a) Coulomb
- b) Volt
- c) Watt
- d) Ohm
  Answer: a) Coulomb
The main use of a transistor in an electronic circuit is:
- a) To amplify signals
- b) To store charge
- c) To resist current
- d) To convert AC to DC
  Answer: a) To amplify signals
The property of a capacitor that determines how much energy it can store is: – a) Capacitance – b) Reactance – c) Impedance – d) Resistance
Answer: a) Capacitance