Accessory DC Power Supply

You can wire these using  just like the 153 or 450 with 153c contactors or insulated rail sections, substituting your 3vdc power for the AC.

You can also use an IR detector (MTH, Lionel, Z-Stuff)
Joe

In the fine print it says they're compatible with A.C. or D.C.  My friend Justin Case would stick a diode in series with the common lead.

You can start your electrical education very simply. To make direct current from alternating current, the procedure is called "rectification."  You can search the web and find a plethora of explanations on how to do it, including lots of pictures of various wave forms that portray the results in easily-understood diagrams.

The basic component is a 10-cent item (or cheaper) called a diode.

One diode in series with A.C. makes "half-wave" D.C.

Four diodes wired in a so-called "bridge" creates "full-wave" D.C.

Full-wave D.C with a capacitor added creates "filtered" D.C.

That wasn't hard, was it?

To go the other way, the process of making A.C. from D.C is called "inversion."  Next lesson...look up "electrical glossary." It will start to make sense.

Thank you guys!  Think I'm going to take your advise Arthur and start doing some homework...want to understand what I'm doing, not just follow instructions.

You don't need separate toggle switches for each signal unless you want to switch them on/off.  Just hook them up to your DC supply.   For example my AC and  DC supplies are activated when I turn my layout ON.  My turnouts and signals are wired directly to my AC and DC supplies and thus are always ON when my layout is ON.  I have toggle switches downstream of my AC and DC supplies to control accessories as desired.   

If your anticipated DC power requirements are modest, leftover wall warts may suffice.  If your DC requirements are more extensive you might considered a larger regulated DC supply.   Regulated implies it should be a high quality filtered supply outputting pure DC (ie flat line, no ripple).   I use a 33 amp, 12 VDC supply I purchased from Micro Mark for around $60: https://www.micromark.com/12-V...ieaje-QaAlfQEALw_wcB .   Like wall warts, larger DC supplies may require 110 VAC input.  You must observe polarity when using DC supplies.

That is quite a find.

Bob, there are converters to change your transformer AC to DC, if you want to go that route help can be provided.  Or, if you do decide on a separate DC power supply, shop around.  There are many adjustable DC wall warts on the market giving a variety of voltage selections.(3 to 12vdc) Additionally, something bigger on the amperage side (30 amp) can be cheaper also.  Just found this one from a US supplier on ebay as an example.  Click on image for larger view.  I use one of these 12vdc-30amp devices myself, and vary the voltages I need to the task at hand.

Is there an example of "converters to change your transformer AC to DC" other than diodes?

On eBay I bought a near-new computer DC power supply to feed track power through three adjustable buck converters to three trolley lines on my layout. Works great, and the trolleys run better at slow speed with DC.

Mike Mottler    LCCA 12394

Use the search term “AC-DC to DC buck converters” in ebay for example.  You’ll get a lot of hits.  Pick the one you like.  As Mike Mottler says a used PC power supply can be had for cheap or maybe free if you have an old computer laying around.  I use one of those for a bench supply.  It has taps for 12, 5, and 3vdc.

This DIY device was designed by OGR member Rod Stewart for a small dc power supply on our layouts.  Pictured is the narrow version.  The write up is in the forum electrical-reference-materials-andamp-manuals

Thanks, TedW. The lightbulb in my head is burning a bit brighter.

Breakout boards are cheap, reliable, and hook right up to an old computer power supply.  I have both of these, but there are many others.

https://www.amazon.com/gp/prod...00?ie=UTF8&psc=1

https://www.amazon.com/gp/prod...01?ie=UTF8&psc=1

John

I have to admit I'm still lost...I think I really need to better educate myself on the basics...if for no other reason than to be able to teach my little man.  I suspect this is easier than I'm making it.  Now thinking about power to street lights, etc

Thank you all!

Keep it simple.  This all started because you bought a couple of LED signals that require DC.  Buy a 12 VDC supply and hook your signals up.  You will learn a lot by just doing that.  I would recommend buying a DC supply big enough to allow growth.  You never can have too much power.

Good advice Steve, thank you.  I think I'll do just that.  At this point learning and understanding is the more important goal while still getting them working for my little man to enjoy.  Again really appreciate everyone taking the time to respond.

Doesn't everybody have a box of old wall-words sitting somewhere? Several of them are very likely 12VDC. They are all labelled.

@shorling posted:

Keep it simple.  This all started because you bought a couple of LED signals that require DC.  Buy a 12 VDC supply and hook your signals up.  You will learn a lot by just doing that.  I would recommend buying a DC supply big enough to allow growth.  You never can have too much power.

I agree Steve, there is never enough power.  Trying to incorporate these Krell Power Meters from Forbidden Planet into my layout.

Chris S.

Thanks again for all replies awhile back...I did more homework and came up with this wiring diagram.  Tested one of them this weekend and it worked...little victories!

These were formerly imported from China and sold by an eBay seller named Wehonest. They may still have them. I bought a bunch of them 18 months ago along with dwarfs and control circuit boards--all from Wehonest on eBay. I don't recall pricing but the Amazon price looks about right. I don't know if Wehonest still carries them on eBay or not.

These are very simple and basic. The ones I got are short and had to be mounted on a simulated silver-painted lineside metal box to be the right height. But maybe these ones are tall enough as-is. At this price, you can't go wrong even if you have to fiddle a bit.

Don Merz

@Arthur P. Bloom posted:

In the fine print it says they're compatible with A.C. or D.C.  My friend Justin Case would stick a diode in series with the common lead.

I strongly suggest you mind Justin's advice.  You only need 1 diode to protect all your signals.  If you have a DIY electronic buddy they would have and gladly give you a suitable 5-cent diode...otherwise something like this would work from a US eBay seller:

Insert diode like this:

Your diagram shows 4 signals.  You can use the remaining 8 (or 11) pairs of the 12-port MTH terminal block to distribute Accessory AC to any other accessories.  That is, you show the Z-1000 brick ONLY powers the MTH terminal block (18V AC track power output unused).  The Z-1000 brick can supply 80 Watts of power thru the Accessory AC output.  4 signals as you indicate will use at most 1 Watt of power!  What are you going to do with the other 79 Watts?!

Arthur’s friend; “Just-in-Case” is a pretty smart feller.  As is Stan2004.  I would certainly put the diode in.  A few pennies worth of insurance.

Possibly a dumb question as I continue to learn more...does that fact that each signal has a resistor on the power wire matter in terms of the suggestion of inserting the diode?

Found these on Amazon...I assume one of these would work?  Pretty cheap

https://www.amazon.com/MIC-Sil...614642441&sr=8-1

For my continued education if you don't mind me continuing to ask questions, how do you know which diode to choose (this one for example is 1000v, they have 200v, 50v, etc.)?  I saw somewhere something about multiplying the voltage by 10...does that mean the 14v power supply x 10 = 140 so would use anything over 140?  Does it matter how high the diode voltage is (i.e. is 200v better than 1000v in this case) or is bigger better?

Thanks again guys...I think (hope) I'm starting to understand this stuff a little better with all of your help!

There are no dumb questions.  If the question occurred to you then obviously something was not made clear in the first place.  Of course this does not apply to questions made in bad faith as it were.

It gets boringly technical, but you are correct that the supplied resistor in the common of the eBay signal head demotes the effect of the AC.  BUT, to your point, a demotion from sergeant to corporal is not the same as being dishonorably discharged!  I think what can be 100% agreed upon is that inserting a 5-cent diode is cheap insurance.  That you have to buy some minimum quantity or pay disproportionate shipping charges is another matter!

As to the voltage rating of the 1N4007 vs. a different 1N400x.  Yes, there's more techno-speak that the cognoscenti can elaborate on.  As it turns out, we're talking about 14V AC or maybe 18V AC at most.  100V, 200V, 1000V are all more than adequate for the task.  Frankly, I've never heard of choosing a part using a 10X rule...but that's just me.  2x or 3x in this case is fine in my opinion.

So the next question is whether there's any downside in using using a 1000V part for a 14V application.  Well, in this particular application NO.  There are applications where you might pay a technical penalty (e.g., wasted power)...but your application is NOT one of them.  It practically comes down to what you can get a good "deal" on!

It does kind of bother me that you are paying $3.78 for what might effectively amount to 1 diode (if you don't have another application for the extras).  That's more than what you'd pay at Radio Shack which is valiantly making its comeback!

I buy 1N400x diodes for less than a penny a piece but then I use them in quantity.  If you're really going to spend $3.78 for 1 diode , I will send you some diodes absolutely FREE!   Just paypal me the 75 cents (or whatever it is) for a non-machinable postage stamp.  Hmmm I don't know if paypal allows such a minimal transaction?!  

Great post here!  Just what I was looking for.  Using the guidance of the electronics gurus on the forum, I made a 4.5 volt DC "transformer" to power my Menards buildings a few months ago.  I am extremely pleased with that project and have since added more Menards lighted stuff simply because I can.  Now my attention has turned to a 12 volt DC power supply (thanks for the examples here) to easily add cheap 12vdc LED strip lights.   I'm thinking I can cut these strips into small pieces and put LEDs wherever I want on the layout by running wires from a bus strip and soldering them to the strips (?).  Any reason why that wouldn't make sense?  As Cannes RR has shown, there's several cool imported items you can add to your layout with this type of power source.

Mike

You guys are amazing....thank you Stan...very helpful response.  Appreciate your concern for the price...I have so little experience with this stuff $3.78 seemed cheap. 😁  In this, and many cases, the convenience may justify it...at least I get free shipping.

@IRON HORSE posted:

Now my attention has turned to a 12 volt DC power supply (thanks for the examples here) to easily add cheap 12vdc LED strip lights.

Mike

I have one that will work on the For Sale Forum, if you're looking for one.

@John H posted:

I have one that will work on the For Sale Forum, if you're looking for one.

John,

I checked out your power supply and it is a little too big for what I want.  It would have been perfect for 12 vdc and 4.5 v dc but I already have the latter.  Thanks for the heads up.

Mike

For DC to run LED lights you probably have a load of sources laying around the house. Any AC adaptor from defunct electronics like cell phone/computer power supplies can provide lots of DC. They run in various voltage/amperage ratings. I've been collecting 12 VDC units. Then you need to determine if the LEDs in the signals are current protected or not. If they are, you may be able to power them directly from the power supply. If not, you can go two ways. You can put a current limiting resistor in series with the negative lead. The value is determined by the number of LEDs in series and the applied voltage. In other words, there's a different resistor value for each voltage and LED quantity.

The other way to go which I'm doing now is to use a CL2N3 LED driver chip. They're cheap (about $0.25 each). And they're sort of magic. Most LEDs can handle only 20 milliamps. (0.020 amps). Anything over that and they go "POOF" really quickly. With the CL2, you can apply any DC voltage from 5 to 90 volts and out the other end comes 20 milliamps. That's it. The number of LEDs you can string in series is dependent on your supply voltage. Each LED drops  around 3 volts. So with a 6 volt supply you can string 2 in series before they would start getting dim. If you have a 90 VDC supply you can string 30 of them in series with the same CL2 chip modulating the current.

The lead on the right goes to your supply. The lead on the left goes to the LEDs. The center lead isn't connected to anything, but provides extra support if you're soldering it to a circuit board.

Armed with a CL2 and a surplus electronic power supply you can run lots of LEDs. If you have a 1 amp power supply, you can power 50 LEDs when they draw 20 milliamps. Lately, due to running more and more building with LED lights, I've been buying these nice 12 VDC dedicated supplies. At 30 watts, it can run tons of LEDs.

Old laptop power adaptors have pretty good outputs and can be used to drive LEDs on train layouts. I've found that Apple power adaptors don't work, or don't seem to. There seems to be a circuit that prevents them from providing power when not hooked up to the Apple charging circuit, but I may be wrong. I've used PC laptop power supplies with no problems whatsoever.

I bought some Chinese LED street lights and they are unprotected LEDs and needed current limiting. They had very fine-gauge leads and I didn't want to solder them below the layout, but the hole 3/32" was too small to put on my crimped ferrules and getting them through the hole to the underworld. Instead I built little circuit modules that have input and output Euro-style terminal blocks and a CL2 N3 driver chip between the positive lead in and out terminals. I put double-sided servo tape on the block and just stick them under the layout where the light leads come through. These are over-engineered to facilitate using stuff I had lying around, namely those Euro-style connection blocks left over from my layout initial construction in Germany. This was my first version. I stopped trying to use insulated wires and went to heavy gauge solid conductors without insulation since they weren't ever to come in contact with each other or other conductors.

This is how I soldered the later versions. I used the adhesive copper foil as a soldering base. I just bent the conductors 90 degrees and used my resistance soldering unit to apply the solder. The middle CL2 lead is just crimped below to help support the chip.