A material whose conductivity lies between conductors and insulators.
Example: Silicon (Si), Germanium (Ge)
PYQ Type: Basic property MCQ
| Type | Example |
|---|---|
| Intrinsic | Pure Si or Ge |
| Extrinsic | Doped with impurities |
PYQ Type: Theory MCQ
PYQ Type: AAI often asks this
Allows current only in one direction — forward bias.
PYQ Type: Working concept MCQ
Special diode used for voltage regulation — works in reverse bias breakdown region.
PYQ Type: Application MCQ area
| Gate | Output |
|---|---|
| AND | 1 only if both inputs 1 |
| OR | 1 if any input 1 |
| NOT | Inverts input |
PYQ Type: Formula tables asked often in theory MCQs
Year Question Asked
2021 Shift 2: p-n junction forward bias behavior
2022 Shift 3: AND, OR, NOT gate logic
2023 Feb Shift 1: Type of doping in n-type
| Concept | Fact |
|---|---|
| Intrinsic Semiconductor | Pure Si or Ge |
| n-type doping | 5-valent impurities |
| p-type doping | 3-valent impurities |
| Diode conducts in | Forward bias |
| Zener works in | Reverse bias breakdown |
| AND gate | 1 only when both inputs 1 |
| OR gate | 1 if any input is 1 |
| NOT gate | Inverts input |
| Concept | GenZ Example |
|---|---|
| Semiconductor — medium conductor | Like mood swings — sometimes conducting, sometimes not |
| Diode allows one-way current | Like a no-entry street |
| n-type = extra electrons | Like bringing extra players to a cricket match |
| Logic gates | Like digital switches — 0/1 decisions |
Focus Areas:
Q1. An intrinsic semiconductor is:
a) Pure metal
b) Pure Si or Ge
c) Doped Si
d) None
Ans: b
Q2. n-type semiconductor is formed by adding:
a) 3-valent impurity
b) 5-valent impurity
c) 4-valent impurity
d) None
Ans: b
Q3. In forward bias, diode conducts when:
a) P to – and N to +
b) P to + and N to –
c) Both to –
d) Both to +
Ans: b
Q4. Zener diode is used for:
a) Amplification
b) Voltage regulation
c) Rectification
d) Filtering
Ans: b
Q5. AND gate gives 1 when:
a) Any input is 1
b) Both inputs are 1
c) Any input is 0
d) None
Ans: b
Q6. NOT gate outputs:
a) Same as input
b) Inverse of input
c) Sum of inputs
d) Product of inputs
Ans: b
Q7. A 3-valent impurity forms:
a) n-type
b) p-type
c) Insulator
d) Metal
Ans: b
Q8. OR gate output is 0 when:
a) Any input is 1
b) All inputs are 0
c) Both inputs are 1
d) One input is 0
Ans: b
Q9. SI unit of resistance is:
a) Ohm
b) Henry
c) Tesla
d) Coulomb
Ans: a
Q10. Which gate is also called inverter?
a) AND
b) OR
c) NOT
d) NAND
Ans: c