RRB JE Electronics MCQ: Multivibrator, Counters & Rectifiers
RRB JE Electronics exam me Multivibrator, Counters aur Rectifiers se direct MCQ aate hain. Agar ye topics weak hain to selection bhool jao. Neeche 20 high-quality MCQ diye gaye hain jo exam pattern ke bilkul according hain.
🔹 Multivibrator MCQ
-
Astable Multivibrator ka output hota hai:
a) Constant DC
b) Sinusoidal wave
c) Square wave
d) Sawtooth wave
Answer: c
Explanation: Astable multivibrator continuously oscillate karta hai bina kisi stable state ke, isliye iska output square wave hota hai. -
Monostable Multivibrator me stable states kitni hoti hain?
a) Zero
b) One
c) Two
d) Three
Answer: b
Explanation: Monostable multivibrator me sirf ek stable state hoti hai aur ek quasi-stable state hoti hai. -
Bistable multivibrator ko aur kis naam se jana jata hai?
a) Flip-Flop
b) Oscillator
c) Amplifier
d) Rectifier
Answer: a
Explanation: Bistable multivibrator do stable states ke kaaran flip-flop kehlata hai. -
555 Timer IC ka use kis multivibrator me hota hai?
a) Sirf Astable
b) Sirf Monostable
c) Astable aur Monostable dono
d) Sirf Bistable
Answer: c
Explanation: 555 Timer IC astable aur monostable dono modes me kaam karta hai. -
Astable multivibrator ka time period depend karta hai:
a) Sirf resistance par
b) Sirf capacitance par
c) R aur C dono par
d) Supply voltage par
Answer: c
Explanation: Astable multivibrator ka time period RC network par depend karta hai.
🔹 Counters MCQ
-
Counter ka basic function kya hai?
a) Signal amplify karna
b) Pulse count karna
c) Rectification karna
d) Oscillation generate karna
Answer: b
Explanation: Counter input pulses ko count karta hai aur binary form me output deta hai. -
Asynchronous counter ko aur kis naam se jana jata hai?
a) Synchronous counter
b) Ring counter
c) Ripple counter
d) Johnson counter
Answer: c
Explanation: Asynchronous counter me clock ripple effect create karta hai, isliye ise ripple counter kehte hain. -
MOD-10 counter maximum kitne states ka hota hai?
a) 8
b) 10
c) 16
d) 32
Answer: b
Explanation: MOD-10 counter 0 se 9 tak count karta hai yani 10 states. -
Synchronous counter me clock kaise lagta hai?
a) Sirf pehle flip-flop par
b) Sabhi flip-flop par ek saath
c) Alternate flip-flop par
d) Randomly
Answer: b
Explanation: Synchronous counter me sabhi flip-flop ek hi clock signal se trigger hote hain. -
Ring counter me kitne flip-flop hote hain?
a) 2ⁿ
b) n
c) n+1
d) n-1
Answer: b
Explanation: Ring counter me n flip-flop hote hain aur sirf ek bit HIGH hoti hai.
🔹 Rectifiers MCQ
-
Rectifier ka kaam kya hai?
a) AC to DC convert karna
b) DC to AC convert karna
c) Amplification
d) Oscillation
Answer: a
Explanation: Rectifier AC signal ko DC me convert karta hai. -
Half wave rectifier me efficiency kitni hoti hai?
a) 40.6%
b) 81.2%
c) 90%
d) 100%
Answer: a
Explanation: Half wave rectifier ki maximum efficiency 40.6% hoti hai. -
Full wave rectifier me ripple factor hota hai:
a) 1.21
b) 0.482
c) 0.812
d) 0
Answer: b
Explanation: Full wave rectifier ka ripple factor 0.482 hota hai jo half wave se kam hota hai. -
Bridge rectifier me kitne diode hote hain?
a) 2
b) 3
c) 4
d) 6
Answer: c
Explanation: Bridge rectifier me 4 diode use hote hain. -
Filter ka use rectifier ke baad kyu kiya jata hai?
a) Voltage badhane ke liye
b) Ripple kam karne ke liye
c) Frequency badhane ke liye
d) Power kam karne ke liye
Answer: b
Explanation: Filter ka main purpose ripple voltage ko reduce karna hota hai. -
Center-tapped transformer kis rectifier me use hota hai?
a) Half wave
b) Bridge rectifier
c) Full wave rectifier
d) Clipper
Answer: c
Explanation: Center-tapped transformer full wave rectifier me use hota hai. -
Rectifier ke output DC ko kya kehte hain?
a) Pure DC
b) Rippled DC
c) AC
d) Noise
Answer: b
Explanation: Rectifier ka output ripple ke saath DC hota hai. -
Bridge rectifier ka PIV requirement hota hai:
a) Vmax
b) 2Vmax
c) Vmax/2
d) 4Vmax
Answer: a
Explanation: Bridge rectifier me diode ka PIV Vmax ke barabar hota hai. -
Rectifier me diode forward bias me kab hota hai?
a) Jab AC negative ho
b) Jab AC positive ho
c) Dono cycle me
d) Kabhi nahi
Answer: b
Explanation: Positive half cycle me diode forward bias hota hai. -
Sabse achhi rectification efficiency kiski hoti hai?
a) Half wave rectifier
b) Full wave rectifier
c) Bridge rectifier
d) Clipper circuit
Answer: c
Explanation: Bridge rectifier practical use me best efficiency deta hai.
1. Multivibrator – Complete Theory
Multivibrator ek electronic circuit hota hai jo do active devices (normally transistor ya IC) ka use karke square ya rectangular waveform generate karta hai. Ye circuit timing, pulse generation, switching aur memory applications me extensively use hota hai.
1.1 Multivibrator ke Prakar
- Astable Multivibrator
- Monostable Multivibrator
- Bistable Multivibrator
1.2 Astable Multivibrator
Astable multivibrator me koi bhi stable state nahi hoti. Circuit continuously ek state se doosri state me switch karta rehta hai, isliye ye continuous square wave generate karta hai.
Working Principle:
Isme do transistor RC coupling ke through connected hote hain. Jab ek transistor ON hota hai to doosra OFF hota hai. Capacitor charging aur discharging ke kaaran ye switching hoti rehti hai.
Time Period Formula:
T = 0.693 (R1C1 + R2C2)
Applications:
- Clock pulse generator
- LED flasher circuits
- Timing circuits
RRB JE Focus: Output waveform, time period aur application par direct MCQ aate hain.
1.3 Monostable Multivibrator
Monostable multivibrator me ek stable aur ek quasi-stable state hoti hai. Isse one-shot multivibrator bhi kaha jata hai.
Working:
Normal condition me circuit stable state me hota hai. Jab trigger signal diya jata hai, circuit temporary state me chala jata hai aur kuch time baad wapas stable state me aa jata hai.
Pulse Width Formula:
T = 0.693 RC
Applications:
- Timer circuits
- Pulse shaping
- Frequency divider
1.4 Bistable Multivibrator
Bistable multivibrator me do stable states hoti hain. Ye memory element ke roop me kaam karta hai.
Special Name: Flip-Flop
Applications:
- Memory storage
- Registers
- Counters
2. Counters – Complete Theory
Counter ek digital circuit hota hai jo input pulses ko count karta hai aur binary form me output deta hai. Counters digital electronics ka backbone hote hain.
2.1 Counter ka Basic Function
Har input clock pulse ke saath counter apni state change karta hai. Ye sequential logic circuit hota hai.
2.2 Counters ke Types
- Asynchronous (Ripple) Counter
- Synchronous Counter
- Up Counter
- Down Counter
- Ring Counter
- Johnson Counter
2.3 Asynchronous Counter
Is counter me clock sirf pehle flip-flop ko diya jata hai. Baaki flip-flop previous output se trigger hote hain.
Disadvantage: Propagation delay zyada hota hai.
2.4 Synchronous Counter
Isme sabhi flip-flop ek hi clock signal se trigger hote hain.
Advantage: High speed operation.
2.5 MOD Counter
MOD counter ka matlab hota hai maximum count value. Jaise MOD-10 counter 0 se 9 tak count karta hai.
RRB JE Focus: MOD calculation aur state diagram par questions aate hain.
3. Rectifiers – Complete Theory
Rectifier ek electronic circuit hota hai jo AC voltage ko DC voltage me convert karta hai. Power supply ka sabse important part rectifier hota hai.
3.1 Rectifier ke Types
- Half Wave Rectifier
- Full Wave Rectifier
- Bridge Rectifier
3.2 Half Wave Rectifier
Isme sirf ek diode use hota hai. Ye AC ke sirf ek half cycle ko DC me convert karta hai.
Efficiency: 40.6%
Ripple Factor: 1.21
Drawback: Zyada ripple, kam efficiency.
3.3 Full Wave Rectifier
Full wave rectifier AC ke dono half cycles ko DC me convert karta hai.
Efficiency: 81.2%
Ripple Factor: 0.482
3.4 Bridge Rectifier
Bridge rectifier me 4 diodes hote hain aur center-tapped transformer ki zarurat nahi hoti.
PIV: Vmax
RRB JE Focus: Efficiency comparison, ripple factor aur diode count par questions aate hain.
3.5 Filters
Rectifier ke baad output pulsating DC hota hai. Filter ka kaam ripple ko kam karna hota hai.
- Capacitor Filter
- Inductor Filter
- LC Filter
- π Filter
0 Comments