# transistor control of coil turnout machie



## tankist

CONSOLIDATED:

looking at options of controlling those peco switch machines and came across this website http://home.cogeco.ca/~rpaisley4/

i really like the idea of relegating the high currents from buttons to semiconductor components so i looked at his transistor controlled circuit. 

this looks prommissing


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## T-Man

Are you sure you do not use a momentary switch?
I'll take a second look.
Second look didn't help.
Are we on DCC with 20 v DC current. The switches I use are AC my old HO AHM switches are AC.


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## T-Man

*Another site*

Bowden hobby circuits
You will be interested in relay control circuits. They use momentary switches.


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## tworail

Moved this to technical model train forum - seems the best place for it.


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## tankist

ordered parts required to build CDU's for 15 turnouts and about 4 charging supplies for them.prototype boards will be coming from ebay but to my surprise discrete parts were Significantly cheaper on your average electronic parts retailer. ordered from newark.com, liked working with it much better then digikey as far as finding best priced alternatives . hopefully processing and shiping will be at least on par.

Followup:
i really like the great length newark went about packaging. inside the package separate carton boxes for lots of items. they seem to be aware and cater to hobby crowd. 
recomended.


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## tankist

Ladies and gentelmen, here it is 
and the most awesome part - surprisingly it even works! 


powered by separate 18V suply for HP printer










here is the voltage comparator based current blocking charge unit with 2 discharge transistors. basically ready to operate 1 turnout as is . LED indicates "charged". while i'm not going to see it normally i chose to keep it for troubleshooting purposes (and since i really like glowing LEDs). activation of coils is by shorting the appropriate double pin headers. the 2 wire terminals on the left connect to additional discharge boards (6 channels - 3 turnouts each). the lone pin header carries the comparator input to the next boards.

no sticky welded buttons and burned out coils for me 
it does look quite ugly but it will be hidden from view anyways. i still need to see if the 25V 2200mF capacitor will throw more then one turnout at once.


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## T-Man

I like it. The board looks professional. :thumbsup:


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## tankist

thats because you don't see other side 
but a great lesson learned - next time i will be developing and etching my own PCB. the extra cost and time spent will be more then compensated by the quality of end product and most importantly time spent.


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## tankist

pluggin on.
middle board needs power feeds and one more sistor per channel


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## tankist

just so it links:


quick vid of my Control panel and CDU during use.
http://www.youtube.com/watch?v=sj_GGW0_nXw&fmt=6


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## Robex

Which pins did you use on the lm393n? asking because i would like to build the same CDU Thanks in return.
Robex


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## NIMT

Here is the pin outs for the LM393N







Here are the pin outs on here for you


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## Robex

Thank you, i will try it and see if i can get it to work.Or as we say in this part of the world lekker like cracker


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## xeniachooch

tankist said:


> Ladies and gentelmen, here it is
> and the most awesome part - surprisingly it even works!
> 
> 
> powered by separate 18V suply for HP printer
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> here is the voltage comparator based current blocking charge unit with 2 discharge transistors. basically ready to operate 1 turnout as is . LED indicates "charged". while i'm not going to see it normally i chose to keep it for troubleshooting purposes (and since i really like glowing LEDs). activation of coils is by shorting the appropriate double pin headers. the 2 wire terminals on the left connect to additional discharge boards (6 channels - 3 turnouts each). the lone pin header carries the comparator input to the next boards.
> 
> no sticky welded buttons and burned out coils for me
> it does look quite ugly but it will be hidden from view anyways. i still need to see if the 25V 2200mF capacitor will throw more then one turnout at once.


Ok. The schematic calls for 4 caps; your design has 7. Why?


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## rkenney

Skip all that. Way too many parts and an awkward power supply.

These are 12v dc units designed by a guy named Ken Stapleton. They work great. My feelin' was by the time I acquired the parts I didn't already have and assemble it on a universal perfboard I would be wastin a lot of space. It would be mine but it wouldn't be very elegant.

He'll sell you just the board, a kit of parts, assembled units or you can get the schematic off his site for nutin.

Very compact. Not exactly surface mount small but gettin there.

One per switch , mounts to control panel (or remote if you like), separate places to mount or wire indicator leds.


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## T-Man

Impressive. :thumbsup:

This guy was under my radar. Until now.


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## DonR

Some of these CDU circuits are a bit of overkill.

Here is a more simple and less costly version that
will power more than one twin coil motor at a time.
You need only one for your layout not matter how
many turnouts you have.

It's available as kit or completed.

http://www.talkingelectronics.com/p...way Projects/75 Model Railway Projects.html#7

I built my own with Radio Shack parts using a
Kalmbach book circuit.

Don


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## gunrunnerjohn

One wonders what the four parallel 2K resistors are for, why not one 500 ohm (or perhaps 470, a nice standard value)?


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## rkenney

560 would be closer to his actual value of 550.

Its a nice circuit, simple, low parts count. the only drawback for me is lack of separate led indicators.


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## gunrunnerjohn

How does 2,000 divided by four come up as 550? They're 2K resistors.


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## rkenney

gunrunnerjohn said:


> How does 2,000 divided by four come up as 550? They're 2K resistors.


Look again they say 2K2. By his notation that is a 2200 ohm resistor. I would have thought you would have known that.


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## gunrunnerjohn

I didn't notice his chart, that's not the way I've ever represented resistors. However, since they're 2.2k, I yield the point.  Why people have to invent their own nomenclature I'll never know.


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