I see. So according to you, cheap non-universal dimmer style phase control will work fine on:
L ballasted flourescent lights electronic ballasted fluorescent lights CFLs motors (need full power start or only limited power reduction) sodium lights mercury lights heaters (you can use it here, but zero crossing makes a lot more sense)
Since the OP wants a universal dimmer, even to cover just lights one needs more than triac style phase control, never mind for other loads.
NT
** No.
That is only according to a m*********ng, anonymous, autistic F****IT calling itself " meow 2222".
IOW - a pile of cat s*it.
....... Phil
Yawn...
If you switch a transformer at zero crossing you get maximum inrush, this is an asymetrical waveform. If you then swich off and on again before the core has stabilised you could sustain the asymetry and saturate the core, note that this occurs even if you use whole cycles so you have to be careful.
** Correct - zero switching *power control* is BAD NEWS when the load is transformer coupled.
The best switch-on point is at a voltage *maximum* ( since the applied voltage averages to zero in one half cycle) and it can take up to 100 full cycles for the core to settle down to an unmagnetised state.
If you care to examine the current drawn by a transformer undergoing an "inrush surge" - it consists of a exponentially decaying stream of pulses at the supply frequency - all with the SAME polarity !
The actually polarity depending on the applied voltage polarity at the moment of switch on.
........ Phil
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