[ §5 · calculators · soft switching ]
SSTC soft switching (k²Q)
calculatorsk²·Q 25.00current lags voltage by 2.3° Essentially clean ZCS.Resonant current far outweighs the magnetising current,so the losses are mostly conduction. Across the range of loaded Q, at k = 0.5: Q 10 k²Q 2.5 lag 21.8° transition Q 20 k²Q 5.0 lag 11.3° transition Q 50 k²Q 12.5 lag 4.6° clean ZCS Q 100 k²Q 25.0 lag 2.3° clean ZCS Q 200 k²Q 50.0 lag 1.1° clean ZCSQ for clean ZCS at k=0.5 40
Tells you whether your SSTC switches softly or hard. The condition is Uspring’s; we derived it from Burnett’s reflected model.
formula
I_res / I_mag = k²·Q φ_lag = arctan( 1 / (k²·Q) )
limits
SSTC only: a primary with no capacitor. With a tuned primary the model does not hold, and the two-pole picture applies instead.
First-harmonic estimate. The real magnetising current is triangular, not sinusoidal.
Q comes from JavaTC, which prints the secondary's Q from its geometry and wire. That is the Q with no arc. An arc loads the secondary and pulls Q down by several times, so the coil moves down the range during a burst. The table under the result shows where it lands at lower Q.