FUNDAMENTALS OF ELECTRONICS

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• Q1: Define Electronics.
  Ans: Electronics is the branch of science and technology that deals with the flow and control of electrons in devices such as semiconductors and circuits.
• Q2: Define Chip.
  Ans: A chip is a small piece of semiconductor material (usually silicon) on which electronic circuits are built.
• Q3: State any four uses of Chips.
  Ans: Uses of chips are:

  • ➔ Used in computers
  • ➔ Used in mobile phones
  • ➔ Used in electronic appliances
  • ➔ Used in control systems
• Q4: Define Conductors. Give some examples.
  Ans: Conductors are materials that allow electric current to flow easily.
  Examples are:

  • ➔ Copper
  • ➔ Aluminium
  • ➔ Silver
• Q5: Define Semi-Conductors. Give some examples.
  Ans: Semiconductors are materials whose conductivity is between conductors and insulators.
  Examples are:

  • ➔ Silicon
  • ➔ Germanium
• Q6: Define Insulators. Give some examples.
  Ans: Insulators are materials that do not allow electric current to flow.
  Examples are:

  • ➔ Rubber
  • ➔ Glass
  • ➔ Plastic
• Q7: Define Covalent Bond.
  Ans: A covalent bond is a chemical bond formed by the sharing of electrons between atoms.
• Q8: Define Ionic Bond.
  Ans: An ionic bond is a chemical bond formed by the transfer of electrons from one atom to another.
• Q9: State the types of Semi-conductors.
  Ans: Types of semiconductors are:

  • ➔ Intrinsic Semiconductor
  • ➔ Extrinsic Semiconductor
• Q10: Define Trivalent Atoms.
  Ans: Trivalent atoms are atoms that have three electrons in their outermost shell.
• Q11: Define Pentavalent Atoms.
  Ans: Pentavalent atoms are atoms that have five electrons in their outermost shell.
• Q12: Define Intrinsic Semi-conductors.
  Ans: Intrinsic semiconductors are pure semiconductors without any impurities.
• Q13: Define Extrinsic Semi-conductors.
  Ans: Extrinsic semiconductors are semiconductors that are doped with impurities to improve conductivity.
• Q14: What is Dooping?
  Ans: Doping is the process of adding impurities to a pure semiconductor to increase its conductivity.
• Q15: Define Conductance.
  Ans: Conductance is the ability of a material to allow electric current to flow. It is the reciprocal of resistance.
  G = 1/R
• Q16: What is an N-Type Semi-conductor?
  Ans: An N-type semiconductor is formed by adding pentavalent impurities to a pure semiconductor, increasing the number of free electrons.
• Q17: What is a P-Type Semi-conductor?
  Ans: A P-type semiconductor is formed by adding trivalent impurities to a pure semiconductor, creating holes as charge carriers.
• Q18: What is a PN Junction?
  Ans: A PN junction is formed by joining P-type and N-type semiconductors together, allowing current to flow in one direction.
• Q19: Define Alloying.
  Ans: Alloying is the process of mixing a semiconductor material with impurity atoms to change its electrical properties.
• Q20: Define Junction or Potential Barrier.
  Ans: A potential barrier is the region at the PN junction that prevents the free flow of charge carriers without external voltage.
• Q21: Define Diode.
  Ans: A diode is a semiconductor device that allows current to flow in one direction only.
• Q22: What is a Forward Biased Diode?
  Ans: A forward biased diode is a diode in which the positive terminal is connected to the P-side and the negative terminal to the N-side, allowing current to flow.
• Q23: What is a Reverse Biased Diode?
  Ans: A reverse biased diode is a diode in which the positive terminal is connected to the N-side and the negative terminal to the P-side, blocking current flow.
• Q24: Define Anode.
  Ans: An anode is the positive terminal of a diode through which current enters.
• Q25: Define Cathode.
  Ans: A cathode is the negative terminal of a diode through which current leaves.
• Q26: Define Rectifier.
  Ans: A rectifier is an electronic device used to convert alternating current (AC) into direct current (DC).
• Q27: Name the types of a Rectifier.
  Ans: Types of rectifiers are:

  • ➔ Half Wave Rectifier
  • ➔ Full Wave Rectifier
• Q28: Define Half Wave Rectifier.
  Ans: A half wave rectifier is a circuit that converts only one half of the AC cycle into DC.
• Q29: Briefly explain the working of a Half Wave Rectifier.
  Ans: In a half wave rectifier, during the positive half cycle, the diode conducts and current flows through the load.
  During the negative half cycle, the diode blocks current, so no current flows.
  Thus, only one half of the AC signal is converted into DC.
• Q30: State the advantages of a Half Wave Rectifier.
  Ans: Advantages of half wave rectifier are:

  • ➔ Simple circuit design
  • ➔ Low cost
  • ➔ Easy to construct
  • ➔ Requires fewer components
• Q31: Define Full Wave Rectifier.
  Ans: A full wave rectifier is a circuit that converts both halves of the AC cycle into DC.
• Q32: Briefly explain the working of a Full Wave Rectifier.
  Ans: In a full wave rectifier, both positive and negative half cycles of AC are used.<br/>During each half cycle, current flows through the load in the same direction.<br/>Thus, a continuous DC output is obtained.
• Q33: State the advantages of a Full Wave Rectifier.
  Ans: Advantages of full wave rectifier are:

  • ➔ Higher efficiency
  • ➔ Better DC output
  • ➔ Less ripple
  • ➔ Uses both half cycles
• Q34: Define Full Wave Bridge Rectifier.
  Ans: A full wave bridge rectifier is a rectifier circuit that uses four diodes arranged in a bridge to convert AC into DC.
• Q35: Briefly explain the working of a Full Wave Bridge Rectifier.
  Ans: In a bridge rectifier, four diodes are used.
  During the positive half cycle, two diodes conduct.
  During the negative half cycle, the other two diodes conduct.
  In both cases, current flows in the same direction through the load.
• Q36: State the advantages of a Full Wave Bridge Rectifier.
  Ans: Advantages of bridge rectifier are:

  • ➔ No center tap transformer required
  • ➔ High efficiency
  • ➔ Better output
  • ➔ Reduced ripple
• Q37: Explain Diode as a Rectifier.
  Ans: A diode acts as a rectifier because it allows current to flow in one direction only.
  It conducts during the forward bias and blocks during reverse bias, converting AC into DC.
• Q38: State any four uses of Semi-conductors.
  Ans: Uses of semiconductors are:

  • ➔ Used in diodes
  • ➔ Used in transistors
  • ➔ Used in integrated circuits
  • ➔ Used in solar cells
• Q39: What are Filter Circuits?
  Ans: Filter circuits are circuits used to remove unwanted AC components (ripples) from the rectified DC output.
• Q40: State the uses of Filter Circuits.
  Ans: Uses of filter circuits are:

  • ➔ To smooth DC output
  • ➔ To reduce ripples
  • ➔ To improve power supply quality
• Q41: Define Ripples.
  Ans: Ripples are the small unwanted AC variations present in the DC output of a rectifier.
• Q42: Define Relays.
  Ans: A relay is an electrically operated switch used to control a circuit by another circuit.
• Q43: Define Capacitor.
  Ans: A capacitor is an electrical device used to store electrical energy in the form of an electric field.
• Q44: Define Shunt Filter Capacitor.
  Ans: A shunt filter capacitor is connected in parallel with the load to reduce ripples by bypassing AC components.
• Q45: Define Series Inductor Filter.
  Ans: A series inductor filter is connected in series with the load and opposes changes in current, reducing ripples.
• Q46: Define Choke Input Filter.
  Ans: A choke input filter uses an inductor (choke) at the input to smooth the output current.
• Q47: Define Pi Filter.
  Ans: A pi filter is a filter circuit consisting of two capacitors and one inductor arranged in the shape of π (pi).
• Q48: Define T-filter.
  Ans: A T-filter is a filter circuit consisting of two inductors and one capacitor arranged in the shape of T.
• Q49: What is Ripple Voltage?
  Ans: Ripple voltage is the residual AC voltage present in the output of a rectifier.
• Q50: What is the Ripple factor? State the formula.
  Ans: Ripple factor is the ratio of AC component to DC component in the output.
  Formula:
  
  r = V_AC / V_DC
• Q51: What is D.C Power Supply?
  Ans: A DC power supply is a device that converts AC into a steady DC voltage for electronic circuits.
• Q52: State the components of D.C Power Supply?.
  Ans: Components of DC power supply are:

  • ➔ Transformer
  • ➔ Rectifier
  • ➔ Filter
  • ➔ Voltage Regulator
• Q53: Define Rectification.
  Ans: Rectification is the process of converting alternating current (AC) into direct current (DC).
• Q54: Define Regulated Power Supply.
  Ans: A regulated power supply provides constant DC output voltage even if the input or load changes.
• Q55: Define Unregulated Power Supply.
  Ans: An unregulated power supply provides DC output voltage that may vary with changes in input or load.
• Q56: What is the D.C Power Supply Circuit?
  Ans: A DC power supply circuit is a combination of transformer, rectifier, filter, and regulator used to convert AC into smooth DC.
• Q57: What is a Transformer?
  Ans: A transformer is an electrical device used to increase or decrease AC voltage using electromagnetic induction.
• Q58: What is a Voltage Regulator?
  Ans: A voltage regulator is a device that maintains a constant output voltage.
• Q59: What is a Voltage Divider?
  Ans: A voltage divider is a circuit that divides voltage into smaller parts using resistors.
• Q60: What is Current Leakage?
  Ans: Current leakage is the small amount of current that flows through an unwanted path due to insulation failure.