Govt. Exams
Entrance Exams
In a 4-bit binary counter, states cycle from 0000 to 1111 (0 to 15). After 1111, it wraps around to 0000 (overflow occurs).
Majority function outputs 1 when majority (2 or more) inputs are 1. Expression: AB + BC + AC covers all cases where at least 2 inputs are 1.
Hamming distance = number of positions where bits differ. 1011101 vs 1001001: positions 3, 5, 6 differ. Hamming distance = 3.
Using Boolean algebra: A + AB + ABC = A(1 + B + BC) = A(1) = A. The dominant term A absorbs all other terms.
A combinational circuit can be completely defined using truth table, Boolean expressions, or logic diagram. All three are equivalent representations.
XOR gate has 2 ones in output (when inputs are different). OR has 3 ones. AND has 1 one. These are odd. XNOR has 2 ones (even). XOR is most commonly cited.
For n-channel depletion MOSFET, when VGS = 0 V (which is greater than Vto = -3 V), the channel is open and device conducts. With VGS > Vto and positive VDS, the device operates in saturation. Depletion-mode devices conduct at VGS = 0.
Germanium has bandgap Eg ≈ 0.67 eV versus silicon's 1.12 eV. Lower bandgap requires less voltage to forward bias. However, silicon is preferred due to better temperature stability and lower leakage current.
IS doubles approximately every 5°C for Si. Over 50°C increase: IS(75°C) = IS(25°C)·2^(50/5) = 2^10 ≈ 1000 times
Bypass capacitor shorts RE to ground at signal frequencies, eliminating degeneration feedback and increasing Av = gm·RC approximately.
