Some commercially available LED lamps are considered non-dimmable. Traditional phase-control dimmers don't work well with them.

Would the behavior of such lamps be different if a full sine wave AC power source, at a lower voltage, were supplied? I.e. could dimming be accomplished using a variac?

  • \$\begingroup\$ Yes it would... \$\endgroup\$
    – user16324
    Feb 4, 2021 at 21:59
  • 3
    \$\begingroup\$ Would the behavior of such lamps be different... How the lamp will behave depends on its design. Is it using a capacitive dropper, buck converter or a linear current regulator? And all lamps would eventually turn off when the voltage gets too low, so I also say: Yes it would... \$\endgroup\$ Feb 4, 2021 at 22:00
  • \$\begingroup\$ I think a capacitive dropper (alone) would still work with a dimmer, so the choices seem to be a buck (current regulator) or a linear (current regulator). Right? \$\endgroup\$ Feb 4, 2021 at 22:17
  • \$\begingroup\$ Depends on the actual lamp. The philips ones i have looked at are constant current, so the brightness will remain constant until the voltage drops too low to maintain the required current. These lamps will also work quite happily with DC input. \$\endgroup\$
    – Kartman
    Feb 5, 2021 at 0:47
  • \$\begingroup\$ If it has a regulator in it, then the regulator will regulate. In your own words, what does a regulator do? \$\endgroup\$
    – user253751
    Feb 5, 2021 at 5:11


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