Dimmer was RE: [simpits-tech] Anyone awake?

[David C. Allen]

Hi Jay
It is a light dimmer for the 737 fwd overhead lightplates. Part of 
the dimmer circuit is copied with permission from Forrest Cook.

I have changed the circuit and added and impedance matching 
transformer between the amplifier and the Oeco Dimmer control. The 
new diagram is located @

http://www.737flightsim.com/Light_Dimmer4a1.pdf

Ask if he has any suggestions to make it simpler, of if something 
needs to be added.

U1: is a LM324N quad op-amp

U2 : is a LM386 - Low Voltage Audio Power Amplifier

Q1: is a MosFet

What I am trying to do is use the original Oeco Dimmer control, it is 
(T31) on the diagram.

Thanks

David

At 01:21 PM 7/2/2006 -0500, you wrote:
>I got a buddy who's an EE.  What are you trying to do with the circuit and
>what do I need to ask him?  I can forward it to him and find out.
>
>Jay
>
>-----Original Message-----
>From: simpits-tech-bounces at simpits.org
>[mailto:simpits-tech-bounces at simpits.org] On Behalf Of David C. Allen
>Sent: Saturday, July 01, 2006 4:46 PM
>To: Simulator Cockpit tech list
>Subject: RE: [simpits-tech] Anyone awake?
>
>Hi Jay
>I would like to use the original 737 autotransformer dimmers for the
>lighting system. I am using DC for the non-dimmed circuits.
>
>I have some large 110VAC 400Hz to 28VAC 400Hz stepdown transformers.
>I also have the 28Vac to 5Vac 400Hz stepdown transformers.
>
>So my ideal 400Hz voltage is 110Volts.
>
>The 400Hz flow is 110Vac to the 110Vac to 28Vac stepdown transformer,
>then the 28Vac autotransformer dimmer, then 28Vac to 5Vac stepdown
>transformer, then to the 5Vac lighting circuits.
>
>Is anyone a electronics expert?
>
>I attached the PDF, but I think it will be striped. So here is a web link
>
>http://www.737flightsim.com/Light_Dimmer3.pdf
>
>I would like to know if you guys think it would work.
>
>It is basically a DC power dimmer operating at 400HZ, and I use the
>400hz to generate the dimmer control voltage using the original 737
>variable autotransformer
>
>David
>
>At 04:17 PM 7/1/2006 -0500, you wrote:
> >True, but how many VA do you need?  I only have a backup ADI that need
> >26/400.  All the other stuff is 115/400 and is stepped down internally.
> >
> >Jay
> >
> >-----Original Message-----
> >From: simpits-tech-bounces at simpits.org
> >[mailto:simpits-tech-bounces at simpits.org] On Behalf Of David C. Allen
> >Sent: Saturday, July 01, 2006 4:06 PM
> >To: Simulator Cockpit tech list
> >Subject: RE: [simpits-tech] Anyone awake?
> >
> >At 02:05 PM 7/1/2006 -0500, you wrote:
> > >My understanding is that the transformers are wound different.  Although,
> > >I've also been told you can run a 60Hz transformer at 400 hz but not the
> > >other way around.  I bought a couple of transformers just for this
>purpose
> > >but never got around to testing them.
> >
> >Yes the low frequency is the governing factor with the transformer so
> >a 60Cps should work at 400Cps
> >
> > >Patience on eBay will turn up static boxes that will do 26vac 400hz.
>I've
> > >managed to snag two of them for under 200 bucks.  They don't show up too
> > >often but when they do, they aren't cheap either.
> >
> >And most are less than 1000VA. :-(
> >
> >
> >David
> >
> > >Jay
> > >
> > >-----Original Message-----
> > >From: simpits-tech-bounces at simpits.org
> > >[mailto:simpits-tech-bounces at simpits.org] On Behalf Of David C. Allen
> > >Sent: Saturday, July 01, 2006 1:57 PM
> > >To: Simulator Cockpit tech list
> > >Subject: Re: [simpits-tech] Anyone awake?
> > >
> > >Hi Gene
> > >My Ham friend has a ton of them, but I would like to find a way to
> > >change a simple 12vdc to 110vac 60Hz Inverter to 400hz. Some say it
> > >is just a RC frequency component change.
> > >
> > >David
> > >
> > >
> > >At 11:50 AM 7/1/2006 -0700, you wrote:
> > > >David C. Allen wrote:
> > > >>Trying to find an inexpensive way to supply 28vAC 400CPS
> > > >Your best bet would be to find a cheap dynamotor on ebay.
> > > >
> > > >g.
> > > >
> > > >
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