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Why would the light fixture make a noise when it is dimmed?
For the exact same reason that theater and set light dimmer packs make more noise when they are at a dimmed level. All dimmers work by adding resistance to the current to prevent electricity from reaching the lamp. The more you dim the light, the more of the current is being dissipated at the dimmer instead of being turned into light energy at the lamp. When the dimmer is full, all of the electricity is passing through the resistance coil and going straight on through to the lamp. The sound is a byproduct of that.
It's an SCR dimmer which works by interrupting the waveform. This action creates harmonics where the hard edge of the chop in the waveform happens. These harmonics can get picked up by the filament in the lamp causing it to vibrate. Part of what you are hearing is the vibration of the filament. Higher quality dimmers put chokes on the dimmer which cut down on the harmonics, but those are more expensive and also take up quite a bit more space.
Sean, actually theatrical dimmers haven't done their work via resistance dimming in a few decades. They do it with SST or SCR dimmer.
Also, in many dimmers, if the sound has gotten louder over the years, the dimmer probably needs to be replaced.
Also? That sound only teenagers are able to hear? I can hear it too. Which really surprised me, because between work and liking loud rock music, I know I've suffered some frequency loss.
Sean, actually theatrical dimmers haven't done their work via resistance dimming in a few decades. They do it with SST or SCR dimmer.
Ooh! What's the difference? I mean, most lighting packs still buzz when dimmed to some degree, so what's going on there?
SCR dimming makes the buzzing much worse, but there is less wasted energy. Basically SCR dimming works by rapidly pulsing the energy on and off at a specific point in the waveform.
Take a look at the dimming section on wikipedia:
[link]
Specifically you are looking at Thyristor dimmers.
What does the term NATted IPs mean? Isn't it the IP addresses within the local network? We are punching firewall holes, and the developer in charge of the ticket swears those are the IPs we need to get from the client so they can get through.
But intuitively that makes no sense to me. Wouldn't you need the external IP addresses?
Needless to say, the firewall rules don't work as implemented.
