Electronics - Study Mode

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[#56] An AC voltage of 220 V(rms) is applied to the primary of a 10 : 1 step-down transformer. The secondary of the transformer is centre tapped and connected to a full-wave rectifier with a load resistance. The DC voltage appearing the load is

(A) $$frac{{22}}{pi }$$

(B) $$frac{{31}}{pi }$$

(C) $$frac{{62}}{pi }$$

(D) $$frac{{44}}{pi }$$

Correct Answer

(D) $$frac{{44}}{pi }$$

[#57] The circuit shown in the figure below function as

(A) an OR gate

(B) an AND gate

(C) a NOR gate

(D) a NAND gate

Correct Answer

(A) an OR gate

[#58] A bistable multivibrator with a saturation voltage ±5 V is shown in the diagram. The positive and negative thresholds at the inverting terminal for which the multivibrator will switch to the other state, are

(A) ±5/11 V

(B) ±10/11 V

(C) ±5 V

(D) ±11 V

Correct Answer

(A) ±5/11 V

[#59] Which of the given relations between the Boolean variables P and Q are not correct? (In the notation used here, P' denotes not P and Q' denotes not Q)

(A) PQ' + PQ = P

(B) (PQ)' = P' + Q'

(C) PQ' = (P' + Q)'

(D) PQ' + Q = P

Correct Answer

(D) PQ' + Q = P

[#60] The circuit, shown is based on ideal operational amplifiers. It acts as a

(A) subtractor

(B) buffer amplifier

(C) adder

(D) divider

Correct Answer

(B) buffer amplifier