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Every Studyloaf post, newest first: exam guides and worked GATE ECE explainers. 62 posts in all.

Newest first

How Far Does the Fermi Level Move When You Dope Silicon?

Each tenfold rise in doping moves silicon's Fermi level by 59.5 mV, since EF − Ei = kT ln(ND/ni): 0.347 eV for 10¹⁶ donors. Worked numbers, limits and mistakes.

ECE topics•October 29, 2026•7 min read
ecegateengineering-fundamentals

How Many Flip-Flops Does a Mod-N Counter Need?

A mod-N counter needs ⌈log₂N⌉ flip-flops: 4 for mod-10, 7 for mod-100. Why ripple counters pass through wrong counts on the way, and how to read them safely.

ECE topics•October 29, 2026•7 min read
ecegateengineering-fundamentals

Why Does a Zener Diode Hold Its Voltage, and When Does It Stop?

In breakdown a Zener's current can swing widely while its voltage barely moves, but only above a minimum. A worked regulator design shows where it stops.

ECE topics•October 29, 2026•7 min read
ecegateengineering-fundamentals

How to Check Your GATE 2027 Response Sheet Against the Answer Key

Where your GATE 2027 responses and the answer key appear, how to mark each MCQ, MSQ and NAT answer against the key, and how to add up your raw marks. From the GATE 2027 brochure.

GATE•October 28, 2026•5 min read
gateanswer-keymarking-scheme

How Do You Enter Answers and Use the Virtual Calculator in GATE?

How GATE 2027 takes MCQ, MSQ and NAT answers, every key on the official virtual calculator, why you type the number before the function, and the slips that cost NAT marks. With the official calculator, the mock test and a practice calculator.

GATE•October 25, 2026•8 min read
gateexam-logisticsmarking-scheme

Why Can't AM Put More Than a Third of Its Power in the Sidebands?

In standard AM the sideband share is μ² ÷ (2 + μ²), and μ can't pass 1 without distortion, so it tops out at 1/3. The derivation and a worked 10 V example.

ECE topics•October 10, 2026•6 min read
ecegateengineering-fundamentals

How Does a Diode's Small-Signal Resistance Change With Bias Current?

A diode's small-signal resistance is rd = nVT ÷ ID: 258.5 Ω at 0.1 mA, 25.85 Ω at 1 mA, 2.585 Ω at 10 mA. The derivation, a worked example and when it fails.

ECE topics•October 10, 2026•7 min read
ecegateengineering-fundamentals

Why Does the Early Effect Give a BJT a Finite Output Resistance?

Raising VCE narrows the base, so IC creeps up and the BJT's output resistance is ro ≈ VA ÷ IC. The physics, a worked 50 V example and the effect on gain.

ECE topics•October 10, 2026•7 min read
ecegateengineering-fundamentals

Why Does a Fourier Series Overshoot by 9% at Every Jump?

The Gibbs overshoot: a square wave's partial sums peak near 1.179, about 9% of the jump, at any number of terms. Computed sums, a worked peak and the traps.

ECE topics•October 10, 2026•7 min read
ecegateengineering-fundamentals

How Does a Hamming (7,4) Syndrome Point to the Flipped Bit?

Each Hamming parity bit checks the positions whose binary index has that bit set, so the syndrome spells out the flipped position. A worked (7,4) example.

ECE topics•October 10, 2026•7 min read
ecegateengineering-fundamentals

What Do Students Get Wrong About Don't-Cares in K-Maps?

Don't-cares in a K-map are optional 1s, not compulsory ones. Four common mistakes, a worked example checked by brute force, and why minimal answers can differ.

ECE topics•October 10, 2026•7 min read
ecegateengineering-fundamentals

How Much Does the Miller Effect Cut Common-Emitter Bandwidth?

A 2 pF base-collector capacitance can act like 195 pF at a CE amplifier's input. A worked Miller effect example, the bandwidth it costs and how exact it is.

ECE topics•October 10, 2026•8 min read
ecegateengineering-fundamentals