[SML] Dimming a 24vac load

[Jerry Durand]

I'll do a drawing just for you.  Please stand by.  Do NOT pace.  Have a
cool drink.

On 07/02/2015 05:55 PM, Dan Sheehan via Stagecraft wrote:
> huh ?
>
> I don't get it, but I should.
>
> this is embarrassing...
> I REALLY should get it...
> I used to test active load components for ATE,
> which are essentially diode bridges
>
> can you post a sketch ?  with waveforms ?
>
> is this a trick to control (dim) an AC load using a DC dimmer ?
>
> I guess AC flowing from power to load through the bridge will attempt
> to produce
> rectified but unfiltered DC at rectifier + and - terminals,
> but biasing this with DC from a DC-controlling dimmer will 
> alter the conductivity paths.. some of the AC will flow to the load,
> some to the DC, depending on voltage...
>
> is your use of the word "floating"  actually critically important,
> meaning the AC source and the DC circuitry cannot have a common ground,
> or magic smoke may be released  ?
>
> am I guessing correctly ?  sort of ?
>
> On Thu, Jul 2, 2015 at 8:19 PM, Jerry Durand via Stagecraft
> <stagecraft at theatrical.net <mailto:stagecraft at theatrical.net>> wrote:
>
>     May not work for this application, but I'll let out a trick on AC
>     loads.
>
>     Assuming you don't mind a little voltage drop AND you have a
>     floating dimmer or AC source...
>
>     Split one wire going to the load, hook the power source to one ~
>     terminal of a bridge rectifier and the load to the other ~ terminal.
>
>     Hook the - lead of the bridge to the dimmer ground and hook the +
>     from the bridge to the dimmer output.  This assumes an NPN type of
>     dimer, if you have a PNP type then you may have to swap wires around.
>
>
>     On 07/02/2015 04:24 PM, Lyric Opera Kansas City via Stagecraft wrote:
>>     Hello Everyone,
>>
>>     I recently posted about dimming a 24v load which many probably
>>     assumed would be a 24v DC load as I did.  I found out that it is
>>     a 24vac load.  They are tiny incandescent lights.  I will be
>>     pulling about 9.5A at 24vac.  I thought I had secured a magnetic
>>     transformer that I could use to dim these lights, but it fell
>>     through.  Anyone know where I could get something that would work
>>     for this application?  I am not sure if there are any other
>>     products that I could get my hands on to do the trick.
>>
>>     Thanks,
>>
>>     Nate
>>
>>
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>
>     -- 
>     Jerry Durand, Durand Interstellar, Inc.  www.interstellar.com <http://www.interstellar.com>
>     tel: +1 408 356-3886 <tel:%2B1%20408%20356-3886>, USA toll free: 1 866 356-3886 <tel:1%20866%20356-3886>
>     Skype:  jerrydurand
>
>
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>
>
>
> -- 
> ...Dan Sheehan
> Fixer of things that break
>
>
>
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-- 
Jerry Durand, Durand Interstellar, Inc.  www.interstellar.com
tel: +1 408 356-3886, USA toll free: 1 866 356-3886
Skype:  jerrydurand

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