The following diagram shows a Zener diode as a voltage regulator. The Zener diode is rated at VZ = 5V and the desired current in load is 5 mA. The unregulated voltage source can supply up to 25V. Considering the Zener diode can withstand four times of the load current, the value of resistor RS (shown in circuit) should be ____ Ω.
Zener Diode diagram for Q37 - JEE Main 2026 Morning
Circuit containing unregulated voltage, series resistor Rs, Zener diode, and load resistor.

Solution & Explanation

Related Formula
Itotal = IZ + IL Vᵢₙ - VZ = Itotal RS
Core Logic

The question is dropped by the examination authority, meaning there was an anomaly in data or multiple correct interpretations, likely due to imprecise wording regarding the maximum source voltage and the exact safe current rating. In a nominal calculation, I_Zmax = 4 × 5 mA = 20 mA. Total current I = 25 mA. RS = (25 - 5) / (25 × 10⁻³) = 800Ω, which is not in the options.

Step 1: Final Conclusion

Question Dropped.

Pattern Recognition

Sees: "Question Dropped" → This often occurs when mathematical data maps to none of the provided MCQs.

Chapter Mix

Class 12 Physics: Semiconductor Electronics: Materials, Devices and Simple Circuits

Reference Study Guides

More Semiconductor Electronics: Materials, Devices and Simple Circuits Previous-Year Questions — Page 7

Q49 jee_main_2024_31_jan_evening Logic Gates
The output of the given circuit diagram is
Logic Gates diagram for Q49 - JEE Main 2024 Evening
The image shows a logic circuit composed of NOT gates, OR gates, and a final NOR gate.
  • A.
    ABY
    000
    100
    010
    111
  • B.
    ABY
    000
    101
    011
    110
  • C.
    ABY
    000
    100
    010
    110
  • D.
    ABY
    000
    100
    011
    110

Solution

Related Formula

Boolean Algebra expressions for logic gates: NOT: A OR: A + B NOR: A + B

Core Logic

Analyze the paths from inputs A and B to the final output Y.

Logic Gates diagram for Q49 - JEE Main 2024 Evening
The image shows a logic circuit composed of NOT gates, OR gates, and a final NOR gate.

Step 1: Intermediate Signals

Top OR gate inputs: A directly, and B inverted (B). Top OR gate output: A + B

Bottom OR gate inputs: A inverted (A), and B directly. Bottom OR gate output: A + B

Step 2: Final Gate Evaluation

The final gate is a NOR gate taking the two intermediate outputs as its inputs.

Y = (A + B) + ( A + B)

Notice that the inner sum simplifies cleanly:

(A + A) + (B + B)

Since A + A = 1 and B + B = 1, the inner term is 1 + 1 = 1.

Y = 1 = 0
Step 3: Conclusion

The output Y is always 0 regardless of the inputs A and B. Checking the truth tables, only option 3 satisfies Y=0 for all conditions.

Pattern Recognition

When a Boolean expression groups a variable and its exact complement together in an OR configuration (A and A), the result instantly hits logic 1. Feeding 1 into any NOR gate guarantees a 0 output universally.

Chapter Mix

Class 12 Physics: Semiconductor Electronics

Q jee_main_2024_31_jan_morning Logic Gates
Identify the logic operation performed by the given circuit.
Logic Gates diagram for Q32 - JEE Main 2024 Morning
Two inputs passing through NOT gates before entering a NAND gate.
  • A. NAND
  • B. NOR
  • C. OR
  • D. AND

Solution

Related Formula
Y = A · B (NAND) Y = A + B (De Morgan's)
Core Logic

The inputs A and B are first passed through individual NOT gates (made from tied-input NAND gates or standard NOT gates). The outputs become A and B.

These are then fed into a NAND gate. The final output Y is:

Y = A · B

Applying De-Morgan's Law:

Y = A + B

Y = A + B

This represents an OR operation.

Pattern Recognition

Bubbled inputs on a NAND gate convert it directly into an OR gate via De-Morgan's laws. (Bubbled NAND = OR).

Chapter Mix

Class 12 Physics: Semiconductor Electronics

More Semiconductor Electronics: Materials, Devices and Simple Circuits Questions — jee_main_2026_23_january_morning

Practice all Semiconductor Electronics: Materials, Devices and Simple Circuits previous-year questions →

Rankbit System
JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%) | JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%)