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