!!

Not Registered?

Welcome!  Please register to view all of the new posts and forum boards - some of which are hidden to guests.  After registering and gaining 10 posts you will be able to sell and buy items on our N'porium.

If you have any problems registering, then please check your spam filter before emailing us.  Hotmail users seem to find their emails in the Junk folder.


Thanks for reading,
The NGF Staff.

Author Topic: The Closet Branch - A layout in my closet.  (Read 23967 times)

0 Members and 1 Guest are viewing this topic.

Offline paulbeckwith

  • Trade Count: (0)
  • Newbie
  • **
  • Posts: 6
  • Country: gb
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #480 on: January 14, 2018, 08:45:28 am »

 hi  dats    2 aa  battery  boxes  on e**y ( uk )    180814661762  only  1.49  free  p&p

   paul       3 aa types also available   

Offline Rich_S

  • Trade Count: (0)
  • Full Member
  • ***
  • Posts: 96
  • Country: us
  • Gender: Male
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #481 on: January 14, 2018, 10:28:29 pm »

The battery box could be wired in parallel or in series.

Webbo

Hi Webbo, That is not true. AA or AAA batteries have a 50mA current rating. If you wire the battery box in parallel, you'll end up with 1.5 VDC and 150mA of current, not enough voltage to light the LED and possibly too much current for the LED to handle? I'd suggest as you originally suggested, wiring the three batteries in series yielding 4.5 VDC and 50mA of current and using the resister to limit the voltage to 3.0 VDC.

This has been a very informative thread guys. Dats please let us know what works best?

 
Cheers,
Rich S.

Online Webbo

  • Trade Count: (0)
  • Full Member
  • ***
  • Posts: 1489
  • Country: au
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #482 on: January 15, 2018, 12:02:15 am »
Hi Rich

I think we have slight misunderstanding of my language you quote. When I say that the battery box could be wired in series or parallel, I didn't mean that both ways would work for Dats. We both agree that a battery box with the cells wired in parallel would not work, but a battery box with at least 3 cells wired in series would.

The current through the LEDs will be determined mainly by the driving voltage, the forward voltage of the LED, and the resistance (external resistor + internal resistance of the battery). There will be a voltage drop across the LED equal to Vf. If Vf = 3.3V , as we might expect for a white LED, then the voltage available to drive current through the resistor and the internal resistance of the battery is 4.5 - 3.3 = 1.2V. The internal resistance of alkaline cells of 1.5V is typically less than 1 ohm. So, if there is no extra resistor and assuming the internal resistance is an ohm, the 1.2V available would be capable of driving a 1A current through the battery. Since it is supplying current to 5 LEDs in parallel the current through each one would be 1/5 as large i.e. 200mA. I have an electronics catalogue that shows the specs on some LEDs. For 3mm LEDs the maximum rated current is 20-30 mA in other words about 10 times less than what we would expect if there was no extra resistor. The smaller LEDs in Dats's lamps would almost certainly have even smaller maximum currents and blow without the extra resistor.

If Dats uses his 620 ohm resistor on a circuit with 3 batteries in series and 5 LEDs in parallel, then I calculate the current through each LED to be = (4.5 - 3.3) / 620 / 5 = 0.4 mA assuming the internal resistance of the batteries is much smaller than 620 ohms. Using a 100 ohm current limiting resistor instead would result in a calculated current of (4.5 - 3.3) /100/5 = 1.2 mA. Or, using a 12 V supply and the 620 ohm resistor we would have a current of (12 - 3.3) / 620 /5 = 3 mA.

Probably as clear as mud.
Webbo
 

Offline Rich_S

  • Trade Count: (0)
  • Full Member
  • ***
  • Posts: 96
  • Country: us
  • Gender: Male
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #483 on: January 15, 2018, 12:42:59 am »
Hi Rich

I think we have slight misunderstanding of my language you quote. When I say that the battery box could be wired in series or parallel, I didn't mean that both ways would work for Dats. We both agree that a battery box with the cells wired in parallel would not work, but a battery box with at least 3 cells wired in series would.
.
.
.

Probably as clear as mud.
Webbo
 

Hi Webbo, Yes I definitely misunderstood your statement that I quoted, sorry :doh:  Being a locomotive electrician your explanation is perfectly clear.  :)


« Last Edit: January 15, 2018, 12:46:34 am by Rich_S, Reason: Added Photo. »
Cheers,
Rich S.

Offline dats475

  • Trade Count: (0)
  • Full Member
  • ***
  • Posts: 311
  • Country: 00
  • Gender: Male
    • YouTube
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #484 on: January 15, 2018, 04:02:53 am »
Hi Paul

Thank you very much for the eBay information.
I ordered a $0.99 battery box with switch today.

Rich and Webbo, thank you very much for your detailed explanation.
My brain is  :scowl: now.
What is vf? What is the "f" stand for? It's not the bad word, is it?

Despite of my  :confused2: condition, I finished my lamp installation.
I couldn't do it without you guys guidance, so once again, thank you all very much for your help!!
I'll report it back soon in detail.

Dats

« Last Edit: January 15, 2018, 04:36:19 am by dats475 »

Online Bealman

  • Moderator
  • Trade Count: (0)
  • Full Member
  • ****
  • N Gauge Society Number: 23151
  • Posts: 12249
  • Country: au
  • Gender: Male
  • Whoops back we go
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #485 on: January 15, 2018, 04:18:26 am »
Forward Voltage.
Vision over visibility. Bono, U2.

Online Webbo

  • Trade Count: (0)
  • Full Member
  • ***
  • Posts: 1489
  • Country: au
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #486 on: January 15, 2018, 04:19:20 am »
Hi Dats

No not the bad word, unless you blow one of your LEDs up in which there might be many words starting with f flying around. As George says, Vf stands for the forward voltage of the LED. It is the minimum voltage required to run the LED and is also the voltage drop across the LED when it's in the circuit.

So white light LEDs with a Vf of 3.3V require a minimum of 3.3V to light them up i.e. at least 3 AAA, AA, C, or D cells wired in series.

Webbo

Offline dats475

  • Trade Count: (0)
  • Full Member
  • ***
  • Posts: 311
  • Country: 00
  • Gender: Male
    • YouTube
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #487 on: January 15, 2018, 08:52:06 pm »
Hi Bealman and Webbo

Thank you for the answer. I never guessed Forward Voltage. I'm sorry for my ignorance but why they write "vf" instead of "fv"?


Ladies and gentlemen and model railroaders!
The Closet Branch almost proudly presents working street lamps!!





It's amazing that I could actually made them work!
Thank you again for all of your help!

Now embarrassing part.
I was thinking about how to make parallel wiring simple but realized that I couldn't even peel apparently a coat of insulation paint on ultra thin wires.
So decided to use some kind of bus wires.
I saw a video of someone using a track as bus wires but I needed thinner material than rails.
So I used a thin cutter that comes with aluminum foil.


I forgot to add a resistor so I redone it.


I wanted make wiring really simple but it became Mr. Frankenstein.


I made this mess for only five lamps!!
If I really want to the night scene complete, I need at least 20 more lights!!
Maybe fiber optic wires with one lamp is the answer. I'd like to explore the possibility in the future.

I'm temporarily using a battery harness from a flash light which I'll replace with an eBay purchased battery box.

Once again thank you for all information and advices!!

Dats


Online Bealman

  • Moderator
  • Trade Count: (0)
  • Full Member
  • ****
  • N Gauge Society Number: 23151
  • Posts: 12249
  • Country: au
  • Gender: Male
  • Whoops back we go
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #488 on: January 15, 2018, 09:19:34 pm »
Looks very effective!
Vision over visibility. Bono, U2.

Online dannyboy

  • Trade Count: (+1)
  • Full Member
  • ***
  • N Gauge Society Number: 25492
  • Posts: 1846
  • Country: ie
  • Gender: Male
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #489 on: January 15, 2018, 09:33:51 pm »
Those street scenes look quite realistic dats  :thumbsup:. As regards your 'Frankenstein' set up, I once used a strip of the aluminium foil that comes free with the cutter (!) as a temporary 'bus wire' - quite effective until you move it  :doh:.
David.
I used to be indecisive - now I'm not - I don't think.

Online Webbo

  • Trade Count: (0)
  • Full Member
  • ***
  • Posts: 1489
  • Country: au
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #490 on: January 15, 2018, 10:23:51 pm »
The lighting looks very effective, Dats. And about the right brightness for you? They look about right to me though the camera can play tricks. Changing the brightness if you want to is as easy as increasing or decreasing the size of your current limiting resistor.

As for your Frankenstein set-up - why not if it works and no one will know except the entire NGF. Sewers beneath the streets aren't very pretty either.

I see your Duster in your street photos. I have just finished painting my '71 Duster and it happens to be light green as well. Cars will likely be the subject of my next post on Deadwood.

Webbo

Online texhorse

  • Trade Count: (0)
  • Full Member
  • ***
  • N Gauge Society Number: 3953
  • Posts: 693
  • Country: gb
  • Gender: Male
    • YouTube
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #491 on: January 15, 2018, 10:33:54 pm »
Dats, nobody looks underneath their own layouts as long as wiring is working, and you shouldn't need to either!  Don't worry about the tape.  It's easily removeable if you need to alter things, and if the lights work, where's the harm? 

You've seen what the bottom of the Montrose and Highland looks like; and now the bottom of Cascade!  That's what curtains and fascias, and in my case State Flags, are for!

Andy
UK
Montrose and Highland Railroad



Offline Rich_S

  • Trade Count: (0)
  • Full Member
  • ***
  • Posts: 96
  • Country: us
  • Gender: Male
    • Awards
Re: The Closet Branch - A layout in my closet.
« Reply #492 on: January 15, 2018, 11:34:10 pm »

I wanted make wiring really simple but it became Mr. Frankenstein.



Dats


Hi Dats,
     I hope your wife was finished with that roll of aluminum foil, or else it's going to be this again...

  :o   :veryangry: 

I think that is actually a very ingenious idea as long as you can solder new wires to the bus bar without unsoldering the wires that are currently connected to the bus.

If you ever decide you would like to redo your bus bar, may I suggest 14 AWG solid copper wire. 

https://www.amazon.com/Copper-Bright-0-064-Diameter-Length/dp/B000IJYRDE   

Copper is one of the best conductors and takes solder very well, plus that roll will last you for the rest of your life.



Cheers,
Rich S.

 

Please Support Us!
January Goal: £55.00
Due Date: Jan 31
Total Receipts: £55.00
Below Goal: £0.00
Site Currency: GBP
100% 
January Donations


Advertise Here
anything