On 11/05/2019 15:46, Archibald Tarquin Blenkinsopp Esq wrote:
On Sat, 11 May 2019 07:28:51 -0700 (PDT), wrote:

On Saturday, 11 May 2019 11:38:18 UTC+1, Fredxx wrote:


As others have said, using a capacitor dropper for a variable load
simply doesn't work.

I've used that arrangement without problems enough times. It's just more issues to address, less situations where it's ok.

It makes the term variable somewhat interesting.

A bank of capacitors to dim a light bulb perchance?

Even high st discounters flog regulators to do that for a few quid.

I cannot think of an instance where you would want to supply a varying
load through an impedance, or even a resistance, with the intention of
dropping the supply Voltage to a useable value. There is just no
point. A Triac or SCR can select the chunk of the sine wave you want
and the scource impedence is so low that it can be ignored.

I seem to rcollect that train sets and model car race tracks used
resistors to drop the supply from 12V, but I would guess that they are
fully electronic now. The lack of back EMF was painfully obvious when
using the early ones.

'Wouldn't like to see the controllers replaced with LW tuning cap's,
it would make for a slow race.

AB

The Mistral digital clock kit I made in 1974 (maybe 1975) used a
capacitor dropper to generate the assorted voltages for the digital side
(GI AY-5-1220 clock) and a the heater and anode voltages for the VFD
display. Not a varying load though.