dimmers

[alanwalker]

two way light switching circuit, can a dimmer switch replace each on/off switch position or only one of them?

 

[journeyman]

Only One.

 

[journeyman]

Sorry, unless you use a touch dimmer with one master and one slave.

 

[alanwalker]

thank you for the information

 

[dzg7pl]

Hi,

New to this forun so bear with me! Could somebody explain to me why the above is not possible as I too would like to have 2 dimmer switches controlling the same set of lights...?

Cheers

Tim

 

[Adam_151]

A dimmer switch works by chopping bits out of the AC waveform, it expects an un broken wave form to start with,

If you feed a dimmer a broken up waveform, you will end up with all the timeings wrong (as it won't be able to detect zero crossing correctly)

Which will probably result in

A) the light flickering like mad
B) the dimmers buzzing like mad
C) The dimmers probably overheating
D) The AC supply becoming electrically noisy

 

[ZenStalinist]

New to this forun so bear with me! Could somebody explain to me why the above is not possible as I too would like to have 2 dimmer switches controlling the same set of lights...?

What you have are those new intellligent dimmers where one of them does the dimming, and they pass on information to each other over the wiring so one knows how much to dim when you press the other. Only one of the dimmers is actually doing the dimming.

 

[ban-all-sheds]

Hi,

New to this forun so bear with me! Could somebody explain to me why the above is not possible as I too would like to have 2 dimmer switches controlling the same set of lights...?

Cheers

Tim

In nutshell, with switches, the electricity comes into one switch, goes out the other side, and then goes into the other switch, and then to the light. Because switches are either on or off, this works fine.

Think of a dimmer switch as a box where you put electricity in at full voltage one side and get less out at the other. If you then take the output and put it into a second dimmer and then onto the light, this won't work, because you aren't putting full mains voltage into the second dimmer, and this is what they need to work.

 

[securespark]

My electricity comes neither with switches nor in a nutshell - you got a speshull deal?? Mine just comes as is....

 

[AdamW]

A dimmer switch works by chopping bits out of the AC waveform, it expects an un broken wave form to start with,

Isn't a dimmer was just a variable resistor? I.e. it varies the amplitude of the AC waveform rather than "chopping bits out of the waveform".

Is the waveform chopper a special dimmer, for something else?

 

[AdamW]

Think of a dimmer switch as a box where you put electricity in at full voltage one side and get less out at the other.

Where does all the spare electricity go? What does one do when the dimmer switch box gets full? Is there a risk of the electricity spilling on the floor and electrocuting me?

I dunno about the rest of you, but I think I'm going to carefully remove all my dimmers and empty the electricity out of them, just to be safe.

Does anyone know where I can get a special bucket to put under the wires whilst I am emptying the switch, to catch any drips of electricity coming out of the wires?

 

[breezer]

no, it really does cut bits out. as they use triacs, try putting an led on the gate of a triac and watch what it does

i must go to bed

 

[plugwash]

there are 4 types of dimmer (that i know of there may be others)

resistive
inductive
capacitive
phase cutting

resistive dimmers produce a huge amount of heat and so would be massive

inductive dimmers would be terrible for switches

capacitive dimmers would be massive at mains frequencys (they are i belive used with high frequency flourescents though)

phase cutters use a triac and only turn on the light for part of the cycle theese are small and not hugely expensive but the harmonics they produce can cause a problem either as noise (big stage dimmer packs buzz like hell) or as EMI/RFI

 

[breezer]

EMI being electro magnetic induction (not a record company)

RFI being Radio frequency interferance

 

[ban-all-sheds]

Does anyone know where I can get a special bucket to put under the wires whilst I am emptying the switch, to catch any drips of electricity coming out of the wires?

You need to use a current sink.