Basic Electronics deals with the study of electronic components, devices, and circuits used in modern technology. This chapter covers semiconductors, diodes, transistors, logic gates, and their applications in amplifiers, rectifiers, and digital systems. It also explains the difference between analog and digital electronics and highlights the role of electronics in everyday life.
1. Which material is commonly used in semiconductor devices?
- A. Silicon ✅
- B. Copper
- C. Aluminium
- D. Iron
Explanation: Silicon is the most widely used semiconductor material due to its abundance and properties.
2. In a semiconductor, conduction increases when:
- A. Temperature increases ✅
- B. Temperature decreases
- C. Light decreases
- D. Pressure increases
Explanation: Higher temperatures provide more energy for electrons to move into the conduction band.
3. The device that allows current to flow in one direction only is a:
- A. Diode ✅
- B. Transistor
- C. Capacitor
- D. Resistor
Explanation: A diode conducts in forward bias and blocks in reverse bias.
4. The basic unit of digital electronics is the:
- A. Logic gate ✅
- B. Diode
- C. Transformer
- D. Capacitor
Explanation: Logic gates process binary inputs to produce binary outputs.
5. Which transistor configuration is most commonly used for amplification?
- A. Common emitter ✅
- B. Common base
- C. Common collector
- D. Differential pair
Explanation: The common emitter configuration provides good voltage and current gain.
6. A rectifier converts:
- A. AC to DC ✅
- B. DC to AC
- C. High voltage to low voltage
- D. Electrical energy to mechanical energy
Explanation: Rectifiers use diodes to convert alternating current to direct current.
7. Which component stores electric charge?
- A. Capacitor ✅
- B. Resistor
- C. Inductor
- D. Transformer
Explanation: Capacitors store energy in an electric field between their plates.
8. In an NPN transistor, the majority charge carriers are:
- A. Electrons ✅
- B. Holes
- C. Protons
- D. Neutrons
Explanation: In NPN transistors, electrons are the main carriers responsible for conduction.
9. Which logic gate gives a HIGH output only when both inputs are HIGH?
- A. AND gate ✅
- B. OR gate
- C. NOT gate
- D. NAND gate
Explanation: AND gate outputs 1 only if all inputs are 1.
10. Which component is used to amplify signals?
- A. Transistor ✅
- B. Diode
- C. Capacitor
- D. Fuse
Explanation: Transistors can amplify weak electrical signals in electronic circuits.
11. The process of joining a small amount of impurity to a semiconductor is called:
- A. Doping ✅
- B. Mixing
- C. Charging
- D. Diffusion
Explanation: Doping increases the conductivity of semiconductors by adding specific impurities.
12. Which device converts DC into AC?
- A. Inverter ✅
- B. Rectifier
- C. Transformer
- D. Amplifier
Explanation: Inverters are used in power supply systems to produce alternating current from a DC source.
13. The NOT gate produces an output that is:
- A. The inverse of the input ✅
- B. The same as input
- C. Always HIGH
- D. Always LOW
Explanation: A NOT gate outputs 0 when input is 1, and outputs 1 when input is 0.
14. Which semiconductor device is used in light detection?
- A. Photodiode ✅
- B. LED
- C. Zener diode
- D. Thyristor
Explanation: Photodiodes generate current when exposed to light, useful in sensors.
15. Which device emits light when current passes through it?
- A. LED ✅
- B. Photodiode
- C. Laser diode
- D. Zener diode
Explanation: Light Emitting Diodes (LEDs) convert electrical energy into light energy.