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Discussion Starter · #1 ·
I have bought a flickering fire effect for my layout and it needs a smooth DC output.

To enable me to be able to control the brightness of the fire I was going to use a spare basic Hornby controller that I have knocking around, but I am not sure if this will give a smooth output or not. Are there any controllers (not too expensive) that give a smooth output?

Also, if the output isn't smooth, will this damage the unit?

Thanks in advance

Chris
 

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Chris,
The output of a basic controller is probably unsmoothed. All you need to do is to get a 1000 to 4700 microfarad condenser (capacitor) - an electrolytic rated at 25 volt will do. Connect this across the controller output (observe the correct polarity +ve to +ve, -ve to -ve) and this will considerably smooth the output for the flickering fire effect.
Using the unsmoothed output probably will not harm the flicker effect unit, but may stop it from working properly. In the long-term a small stabilised power supply working off the 16 Volt AC auxilary supply of a controller may be better. Look out for books such as 'Model Railway Electronics' by Roger Amos or 'Wiring the Layout' by Jeff Geary; both of these give circuits for small power supplies.
Regards,
John Webb
 

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Discussion Starter · #3 ·
Cheers for the reply John - I shall have to take a trip to my local Maplins and see what I can find.

Am I right in thinking that the larger the number the smoother the output will be?
 

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Yes, the higher the value (number) the smoother. But as your flicker effect probably does not take much power, you do not need to have an enormous capacitor.

I'm fairly certain Maplin do small smoothed power supplies or kits to make them. The latter are good practice if you are relatively new to electronics, so it might be worth having a look round while you're at your local Maplins.

Regards,
John Webb
 

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Discussion Starter · #5 ·
Cheers for that John - yes I am new to electronics so maybe a kit will be a worthwhile exercise.

I'll pop along next weekend and see what I can find.
 

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If you haven't got a multimeter at all, I would strongly recommend getting one. These are extremely useful for checking polarity, connections, resistors etc. For model railway work one with a current (amps) range of an amp or two is quite adequate. Multimeters are also useful round the home for checking batteries in radios and the like if you are having problems.

Regards,
John Webb
 

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Hi Chris
You havent actualy said what voltage your power supply needs to be?
However this site can supply ready made units in various output voltages, which no doubt would suit your needs Regulated power supplies
I make my own for a couple of pounds or so. e.g a 12v regulated (Stabilised) PSU = 1 x Positive 12v voltage regulator about £0.60, heatsink to fit regulator around £0.55, bridge rectifier - £0.25, three capacitors about £1.10 and a piece of strip board - free as off cut from larger sheet, total cost of project around £2.50ish. All components from Maplins.


As John has said the purchase of a Multimeter is a great investment for both model railway and home use. They dont need to cost the earth either!
 

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Discussion Starter · #8 ·
I do have a multimeter - find it very useful for finding dead sections of track.

The module I have is from Modelex (MDX 7 & 8) and from the instructions it says - Connect to 12volt D.C. Smoothed supply as shown in the diagram the lamps should now begin to flicker.

Originally I was going to connect it to the DC output on my HM2000 controller, but someone told me that this wasn't a smooth output. When I saw a fire effect on another layout, it was connected to a Graham Farish controller on the variable supply, which seemed like a good idea as the intensity of the fire can be adjusted.

Hope that clarifies, and thanks for all the help so far.

Chris
 

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Hi Chris
For 12v smoothed supply connect at least a 470uf eletrolitic capacitor (Or larger value) and rated at least at 35v working or higher across the dc input connections of the flicker unit. Ensure you have the capacitors positive lead connected to the positive suplpy lead. Caps shuch as thesea re ideal Elect. Capacitors
Your multimeter will show which way around your your H & M2000 uncontrolled supply is wired.

All the best
 
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