# Power conversion



## JPR (Nov 5, 2019)

I have been running HO for many years, but recently had to scale down to a move to a much smaller living place.
SO... I went all in and embraced Z Scale.

Question is: As I have many old 12v power controllers, and I am not ready to convert to digital yet, I would like to use one of my 12v controllers to power my Z scale. I am aware that z scale should be only 8-10v, so what I want to know, is how hard is it to convert or change an old controller? Is there a resister or step down module i can buy? Any suggestions?


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## gregc (Apr 25, 2015)

how electronic savy are you?


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## Shdwdrgn (Dec 23, 2014)

The easiest solution might be to use a zener diode to lock down the maximum output voltage to 9VDC. You would only notice the top 1/8 of your throttle throw no longer has any effect. Alternatively you could use some high-wattage resistors to make a voltage divider which would again limit the highest output but this would let the full throw of the throttle still be responsive. You should be able to find plenty of images of either solution on google so you can see what is involved.


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## gregc (Apr 25, 2015)

Shdwdrgn said:


> The easiest solution might be to use a zener diode to lock down the maximum output voltage to 9VDC.


what limits the current thru the zener? maybe a regulator


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## Shdwdrgn (Dec 23, 2014)

I haven't really worked with zeners before, I just know that's a common usage for them. As far as I know, they don't have any effect on the current, they just act as a very simplistic voltage regulator within a limited range.


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## jimben (Jun 27, 2018)

I posted resistor conversion in Z Scale forum. Zeners use a dropping resistor to limit the current. You do not need a zener.


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## Dennis461 (Jan 5, 2018)

Tell us more about the equipment. It may be simpler to reduce the 120VAC from the wall outlet.


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