Circuits & Electrical Power · The Resonance Bench
Exam-hall rules, last bench
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Exam-hall rules, last bench

This is the boss. No calculator. Today the bench convention is 12π0.16\dfrac{1}{2\pi} \approx 0.16, and therefore 2π6.252\pi \approx 6.25 — the round stand-ins engineers keep for head arithmetic and site sanity checks. The L and C values are chosen so that LCLC and L/CL/C are both perfect squares, which means every root comes out whole and every line lands on a clean number.

One tank, one long problem, and every answer feeds the next: the resonant frequency, then the coil's reactance at it, then the capacitor's reactance as a cross-check — they must agree, and if they do not, one of your first two lines is wrong — then the bandwidth the sheet's Q allows. Write each line down as you go; one early slip rolls all the way to the verdict.

And note what the last line actually asks. It does not want another number; it wants a DECISION about whether this tank may be installed, the way a real bench check does. The arithmetic is only there to earn you the right to make it. 5★ under par here is the chapter crown. Clock in.

no calculator in the boss room — the numbers are chosen to fit in your head