Design a VIC: cell, choke, Q and step charging
Given this tube, this water and a target frequency, what choke does it need, how sharply will it ring, and will it step-charge?
- L
- Required choke inductance, H
- f
- Target frequency, Hz
- C
- Cell capacitance, F
LaTeX
L = \frac{1}{(2\pi f)^2 \cdot C}
Method
- Find the cell's capacitance from the two tube diameters, the overlap length and the water's permittivity at temperature — the coaxial capacitance calculation.
- Find the choke that rings that capacitance at the target frequency: L = 1 ÷ ((2πf)² C) — the required inductance calculation.
- With that choke, that cell and the series resistance, find the Q and the resonant voltage rise — the Q factor calculation.
- Ask what the water is doing at that frequency: its Cole-Cole loss tangent. A cell full of tap water at a few kilohertz is a resistor with a capacitor attached, and the Q above is optimistic by however much this says.
- Run the pulse train against the cell and its leak resistance: does the charge accumulate into a staircase, or drain away between pulses — the step charging calculation.
- Each step is its own calculation with its own page. Every formula is shown below with these numbers in it, and each links to that page pre-filled, so any step can be checked alone.
Assumptions
- Every assumption of every constituent applies. In particular: the cell is an ideal coaxial capacitor with no end effects; the choke is lossless and its self-capacitance is ignored; the water's permittivity follows the linear temperature fit and the Cole-Cole relaxation; the step-charge pulses are ideal.
- The series resistance and the leak resistance are two different things and are entered separately. The first is what damps the ring — choke wire, cell ESR, wiring; the second is what drains the cell between pulses — the water's conductance across the gap.
- The loss tangent step is diagnostic, not fed forward. The Q reported is the lossless-dielectric figure from the series resistance alone; a loss tangent near or above 1 means the real Q is far lower, and the page says so rather than blending the two.
- This is standard physics chained together. What is Meyer's is the claim about what the cell is — a water capacitor to be rung, not an electrolytic cell to be driven — and that claim lives in the sources, not in the arithmetic.