60 Professional Questions with Complete Answers
Basic Knowledge
Q1. Transistor ka Reference Designator kya hota hai?
Answer:
Q
Example:
- Q1
- Q25
- Q301
Q2. BJT ki Full Form kya hoti hai?
Answer:
Bipolar Junction Transistor
Q3. Transistor ka main kaam kya hota hai?
Answer:
- Electronic Switching
- Signal Amplification
- Voltage Control
- Current Control
Q4. Laptop motherboard mein BJT kahan use hota hai?
Answer:
- Power Button Circuit
- Reset Circuit
- Enable Signal
- Charging Signal
- Fan Control
- Audio Circuit
- Backlight Circuit
- Logic Circuit
Q5. BJT ke kitne terminals hote hain?
Answer:
3
- Base (B)
- Collector (C)
- Emitter (E)
Q6. Base ka kya kaam hota hai?
Answer:
Base Control Terminal hota hai.
Chhota current de kar Collector aur Emitter ke darmiyan current ko control karta hai.
Q7. Collector ka kya kaam hota hai?
Answer:
Main current Collector se Emitter ki taraf flow karta hai.
Q8. Emitter ka kya kaam hota hai?
Answer:
Current ko circuit mein return karta hai.
Q9. BJT kis cheez se control hota hai?
Answer:
Current se.
MOSFET Voltage se control hota hai.
Q10. BJT aur MOSFET mein sab se bara difference kya hai?
Answer:
- BJT = Current Controlled Device
- MOSFET = Voltage Controlled Device
Types of BJT
Q11. BJT kitne types ka hota hai?
Answer:
2
- NPN
- PNP
Q12. NPN Transistor kya hota hai?
Answer:
Sab se common BJT.
Jab Base ko current milta hai to Collector aur Emitter conduct karte hain.
Q13. PNP Transistor kya hota hai?
Answer:
Negative logic ya High-side switching mein use hota hai.
Q14. Laptop motherboard mein kaunsa type zyada use hota hai?
Answer:
NPN Transistor.
Q15. Schematic mein NPN aur PNP ka farq kaise pehchante hain?
Answer:
Emitter arrow se.
- NPN → Arrow bahar ki taraf.
- PNP → Arrow andar ki taraf.
Working Principle
Q16. Transistor ON kab hota hai?
Answer:
Jab Base-Emitter junction forward bias ho.
Q17. Silicon BJT ka Base-Emitter Voltage kitna hota hai?
Answer:
Lagbhag 0.6V se 0.7V.
Q18. Collector-Emitter ka current kis cheez par depend karta hai?
Answer:
Base Current par.
Q19. Amplification kya hoti hai?
Answer:
Chhote signal ko bara signal banana.
Q20. Switching Mode kya hota hai?
Answer:
Transistor sirf ON ya OFF state mein kaam karta hai.
Testing
Q21. Transistor ko kis mode mein check karte hain?
Answer:
Diode Mode.
Q22. Good NPN Transistor ki Base-Emitter reading kitni hoti hai?
Answer:
0.6V–0.7V
Q23. Good NPN ki Base-Collector reading kitni hoti hai?
Answer:
0.6V–0.7V
Q24. Collector-Emitter reading kaisi honi chahiye?
Answer:
Open (OL) ya design ke mutabiq.
Q25. Agar tino pins short hon to?
Answer:
Transistor kharab hai.
Q26. Agar Base open ho jaye to?
Answer:
Transistor switch nahi karega.
Q27. Board par transistor kaise check karte hain?
Answer:
Diode Mode se Base-Emitter aur Base-Collector check karte hain.
Q28. Doubt ho to?
Answer:
Component ko board se remove karke check karo.
Q29. Datasheet ki zarurat kyun hoti hai?
Answer:
Pinout aur specifications verify karne ke liye.
Q30. SOT-23 package mein pin identify kaise karte ho?
Answer:
Datasheet ya board schematic se.
Practical Questions
Q31. Power Button Circuit mein transistor kyun use hota hai?
Answer:
Power button signal ko process aur switch karne ke liye.
Q32. Fan Control Circuit mein transistor ka kya role hota hai?
Answer:
Fan ko ON/OFF aur speed control karna.
Q33. LED Control mein transistor kyun use hota hai?
Answer:
LED ko drive karne ke liye.
Q34. Audio Circuit mein transistor kis liye hota hai?
Answer:
Signal Switching aur Amplification.
Q35. Reset Circuit mein transistor ka kya kaam hota hai?
Answer:
Reset Signal ko generate ya control karna.
Fault Finding
Q36. Transistor short ho jaye to symptoms?
Answer:
- Laptop ON na ho
- Fan hamesha chale
- LED hamesha ON rahe
- Charging issue
- Signal missing
Q37. Transistor open ho jaye to?
Answer:
- Enable Signal missing
- Fan na chale
- Power Button kaam na kare
Q38. Collector par voltage hai lekin Emitter par nahi. Kya check karoge?
Answer:
- Base Voltage
- Base Resistor
- Transistor khud
Q39. Base Voltage hi nahi aa rahi. Kya check karoge?
Answer:
- KBC Output
- EC Signal
- Pull-up Resistor
- Previous Stage
Q40. Fan continuously full speed par chal raha hai. Kya transistor fault ho sakta hai?
Answer:
Haan, transistor ya fan control circuit fault ho sakta hai.
Shop Level Questions
Q41. Boardview mein transistor kaise search karte ho?
Answer:
Reference Q
Example:
- Q120
- Q340
Q42. Schematic mein transistor ka symbol kaise pehchante ho?
Answer:
Teen terminals aur emitter arrow dekh kar.
Q43. Kya har Q number MOSFET hota hai?
Answer:
Nahi.
Q Reference BJT ya MOSFET dono ho sakta hai.
Datasheet aur symbol dekhna zaroori hai.
Q44. Datasheet mein HFE kya hota hai?
Answer:
Current Gain (Beta).
Q45. Collector Current Rating kyun important hai?
Answer:
Taake transistor overload na ho.
Q46. Kya kisi bhi transistor ki jagah doosra laga sakte hain?
Answer:
Nahi.
Part Number, Polarity, Current Rating, Voltage Rating aur Package match hona chahiye.
Q47. Transistor replace karne ke baad bhi fault hai. Kya karoge?
Answer:
Base drive signal aur surrounding circuit check karunga.
Q48. Professional Technician transistor replace karne se pehle kya karta hai?
Answer:
- Datasheet dekhta hai.
- Input aur Output voltages measure karta hai.
- Root cause identify karta hai.
Q49. Professional Rule
Question:
Transistor troubleshoot karne ka golden rule kya hai?
Answer:
"Collector, Base aur Emitter ki voltage compare kiye baghair transistor ko faulty declare mat karo."
Q50. Interview Question
Question:
Base par 0V, Collector par 3.3V aur Emitter par 0V hai. Kya transistor ON hai?
Answer:
Nahi.
Base drive nahi mil rahi, is liye transistor OFF hai.
Q51. BJT aur Relay mein kya difference hai?
Answer:
- BJT Electronic Switch hai.
- Relay Mechanical Switch hai.
Q52. Darlington Transistor kya hota hai?
Answer:
Do BJTs ka combination jo high current gain deta hai.
Q53. Digital Transistor kya hota hai?
Answer:
Aisa transistor jiske andar base resistor pehle se integrated hota hai.
Q54. Kya laptop motherboard mein Digital Transistor use hote hain?
Answer:
Haan, kuch logic aur signal circuits mein.
Q55. BJT ka saturation mode kya hota hai?
Answer:
Jab transistor fully ON ho aur Collector-Emitter voltage bohat kam reh jaye.
Q56. Cut-off mode kya hota hai?
Answer:
Jab transistor bilkul OFF ho aur current flow na kare.
Q57. Active Region kya hoti hai?
Answer:
Jahan transistor amplification ke liye kaam karta hai.
Q58. Shop Practical
Question:
Power button press karne par KBC signal de raha hai, lekin agla enable signal nahi aa raha. Kis component ko check karoge?
Answer:
Signal line par lage BJT transistor, uske base resistor aur surrounding pull-up/pull-down network ko.
Q59. Advanced Practical
Question:
Fan nahi chal raha. Fan ko direct 5V dene par chal jata hai. Agla diagnostic step kya hoga?
Answer:
Fan driver transistor, PWM signal aur fan control IC ko check karunga.
Q60. Shop Final Practical Question
Question:
Laptop mein charging LED nahi jal rahi, charging IC theek hai aur adapter bhi theek hai. Tumhara troubleshooting sequence kya hoga?
Answer:
- LED supply voltage check karunga.
- LED resistor check karunga.
- LED control transistor ki Base, Collector aur Emitter voltages measure karunga.
- KBC ya Charger IC se aane wala control signal verify karunga.
- Schematic follow karke signal path trace karunga.
- Zarurat par transistor ko remove karke Diode Mode mein test karunga.
📚 Chapter 9 (Next)
Ab hum Voltage Regulator / LDO & Buck Converter par jayenge.
Yeh chapter 70+ professional questions ke saath hoga aur ismein:
- Linear Regulator (LDO)
- Buck Converter
- Boost Converter
- PWM Controller
- Enable Signals
- Power Rails (3.3V, 5V, VCORE, VCCSA, VCCIO)
- Real Dell motherboard troubleshooting
- Schematic-based diagnostics
Yeh chapter tumhare student ko professional motherboard power troubleshooting tak le jayega.
0 Comments