Help on a low current dimmer circuit

Started by ApEkV2 · 24 January 2009 · 4 posts · last reply 26 January 2009

1. ApEkV2

   #1 · 24 Jan 2009

   Hello, does anyone know of any very low current dimmer circuits out there?
   This is partly solved, and I've posted links for anyone building circuits like these (post #4).
   Here is the one I made from scratch, but it doesn't work below 120 watts.
   I would like to build one that could run at under 100 watts of current.
   (It uses regular 115vac house current at 60hz) I'm also planning on using 220vac with this dimmer as well.
   Does this circuit pass for this kind of voltage?
   
   
   
   The application would be for a plasma electrolysis experiment I am conducting.
   It seems that right when the reaction is at its peak, the power drops off to a point where the dimmer can't run because of the low amp draw.
   If it were to function under low current conditions, I think the reaction could be better.
   
   The full circuit this dimmer would be in is here at 40 seconds into video.
   
   YouTube - Plasma HHO (3)
   
   Is this an unfixable trait of triacs? Or can there be a workaround.
   
   Matt

2. Joit

   #2 · 24 Jan 2009

   I am no Pro with Circuits, but would try a lower Resistor as the 4,7k, maybe 3,5k at first.
   
   Nice Video what you did there, how long do the Electrones left, when they are lighting?
   Someone told me, it takes 15 Secs, till they been gone.

3. ApEkV2

   #3 · 24 Jan 2009

   Thanks I'll try switching that resistor on the breadboard circuit (the original circuit was on a breadboard).
   The plasma coming from the cathode doesn't eat the copper away at all.
   If anything, the 304 stainless is electroplated onto the copper electrode.
   Of course, I think when I try 220vac instead of 115 that could change.

4. ApEkV2

   #4 · 26 Jan 2009

   diac relevance to the circuit
   
   Changing the resistor didn't have near the same effects as changing the diac. I tried three different diac solutions.
   
   
   
   From left to right, a real diac from a light dimmer - a neon lamp - and a homemade diac built with two inverse parallel shockley diodes.
   All yielded different results, but the one that worked best with the rest of the circuit was the far right diac.
   The first two didn't work so well with the resistor / capacitor arrangement I have.
   They altered the triac firing pulse too much giving me little to no adjustment.
   A way to solve that would be to redesign the whole trigger circuit with different resistance / capacitance values.
   If I were to redesign the circuit, I think the neon lamp would be the best diac to go with as it is the simplest solution.
   
   Here are links for anyone trying to build an unorthodox dimmer.
   
   How do light dimmers works?
   The Shockley Diode : THYRISTORS
   Resistors
   Odd application of neon glow lamps
   TRIAC - Wikipedia, the free encyclopedia
   The DIAC : THYRISTORS