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Am I correct in wiring my two anodes together?

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Am I correct in wiring my two anodes together?
Posted by wolfman hal on Tuesday, October 19, 2021 10:23 AM

In another thred I found out that my LED'S were bad on my panel. 

Am I correct that that the two Anodes will be connected together to change the LED'S from Green to Red as I throw the Switch. I can not tell on the existing panel as I have the wires covered.

Harold

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Posted by CSX Robert on Tuesday, October 19, 2021 10:52 AM

wolfman hal
Am I correct that that the two Anodes will be connected together to change the LED'S from Green to Red as I throw the Switch

Most likely not, but we would need more information on how the circuit is wired to answer with absolute certainty.

The most common way to wire LEDs and Tortoises has the LEDs wired in parallel, but opposite polarity (anode to cathode and cathode to anode).  This causes the current to flow through one or the other LED depending on the direction of the curent.

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Posted by SeeYou190 on Tuesday, October 19, 2021 11:06 AM

CSX Robert
The most common way to wire LEDs and Tortoises has the LEDs wired in parallel, but opposite polarity (anode to cathode and cathode to anode).  This causes the current to flow through one or the other LED depending on the direction of the curent.

This is the only way I have done it.

-Kevin

Living the dream.

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Posted by wolfman hal on Tuesday, October 19, 2021 12:14 PM

Ok hear is the layout.

1 6 position DPDT Toggle

2. 10 VDC to bottom postions Call 1 & 2

3. Criss Cross wires to 5 & 6  Top

4. One Side of LED to 3 on Toggle

5. Other side of LED connected to other LED

6  Other side of LED connected Terminal 1 of Tortoise 

7. Position 8 of Tortoise back to position 4 of Toggle

I can not tell which leads are connected together

 

Harold

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Posted by RR_Mel on Tuesday, October 19, 2021 1:08 PM



Mel


 
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Posted by CSX Robert on Tuesday, October 19, 2021 1:40 PM

wolfman hal

Ok hear is the layout.

1 6 position DPDT Toggle

2. 10 VDC to bottom postions Call 1 & 2

3. Criss Cross wires to 5 & 6  Top

4. One Side of LED to 3 on Toggle

5. Other side of LED connected to other LED

6  Other side of LED connected Terminal 1 of Tortoise 

7. Position 8 of Tortoise back to position 4 of Toggle

I can not tell which leads are connected together

 

Harold

 

Ok, in that case they should be anode to cathode and cathdoe to anode.  It's the same as Mel's circuit above except you have the power crossed on the input to the toggle instead of the output, which makes no difference.

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Posted by Overmod on Tuesday, October 19, 2021 1:54 PM

Anode to cathode close to the LEDs (effectively making them a big 'bipolar LED' if they were two separate LED devices).

As far as 'the rest of the circuit is concerned' there is ONE wire to a switch terminal, and ONE wire at the other side of the LEDs to the Tortoise.  No 'anode' or 'cathode' is wired to anything directly, and effective polarity (which here produces direction of rotation of the Tortoise here) determines which of the two LEDs will conduct and light.

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Posted by wolfman hal on Tuesday, October 19, 2021 2:51 PM

I will be out of town for a cou[le pf days so please check back to see if it worked.

Thanks

Harold

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Posted by wolfman hal on Tuesday, October 19, 2021 4:02 PM

Ok Still a problem

Rewired and double checked per all your advise. The switch throws the turnout

correctly.  The problem is that neither LED lights even when switch is thrown.

The only difference between this switch on all the others on the layout approx 20

is that this is from a new pack that came from China. 

It reads RED Voltage 2.0-2.2  Green Voltage 3.0-3.4v  

Max current 20mA

I am using 5mm bulbs.

I have been using these on other projects with a resistor with no problem. This is the first time I am using this on my control panel.

The control panel has NO RESISTORS as I am using Tortoise Switch Machines.

I have No Resistor on any switch and they all work fine.

Any Ideas guys

Harold

 

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Posted by Overmod on Tuesday, October 19, 2021 4:12 PM

Take the LED assembly out or isolate it, and apply controlled voltage (e.g. via the button-cell field testing trick).  If the assembly doesn't light red in one direction and green in the other, you've turned both diodes into dark-emitting resistors... assuming the Tortoise still gets current that opens and closes it correctly.  (I have never seen LEDs fail to continuity, but if they're dark and the Tortoise runs at least one of them is conducting but not emitting...)

With the LEDs removed or bridged, measure the voltage and current in the circuit, including any transients as things start and stop.  Even short overvoltage or excessive current can ruin the tiny junction that is the actual "LED" in the package.

You can fake the functionality with a pair of regular diodes with light bulbs like Mel's recommended 1157s in series, connected at a distance to be anode-to-cathode.  The light bulbs will glow 'directionally' and be more robust if there is overcurrent...

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Posted by wolfman hal on Tuesday, October 19, 2021 4:59 PM

OK Give me a clue what is a e.g. via the button-cell field testing trick). 

Thanks in advance. Please use the KISS answer.

Harold

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Posted by RR_Mel on Tuesday, October 19, 2021 5:04 PM

Make sure your LEDs work.  Use a 1K resistor in series with the LED connected to your power source.  If they light up normally then try one LED in series with your Tortoise.  It should only light up with one polarity or one direction of movement of the Tortoise.

I have found LEDs that will conduct but not emit, its rare normally when they have been subjected to too much current they go open.

I use a single bi-color red/green two lead LEDs for my Tortoise machines.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=bi-color+led+2pin&_sacat=0&LH_TitleDesc=0&_odkw=bi-color+led&_osacat=0&_sop=15

One LED two colors.

Mel


 
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I'm beginning to realize that aging is not for wimps.

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Posted by RR_Mel on Tuesday, October 19, 2021 5:16 PM

A quick check to see if an LED is working is to use the lowest ohm reading on a cheapo multimeter.  The LEDs will glow a bit.

Mel


 
My Model Railroad   
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I'm beginning to realize that aging is not for wimps.

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Posted by wolfman hal on Tuesday, October 19, 2021 5:36 PM

Will this work with the LED's left in the circuit

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Posted by gregc on Tuesday, October 19, 2021 5:53 PM

wolfman hal
4. One Side of LED to 3 on Toggle

5. Other side of LED connected to other LED

6  Other side of LED connected Terminal 1 of Tortoise 

this says the two LEDs are wired in series.

if either both their anodes or cathodes are connected, no current will flow.

if they are connected anode to cathode, current will only flow in one position of the toggle switch.

am i interpreting this correctly?

greg - Philadelphia & Reading / Reading

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Posted by Overmod on Tuesday, October 19, 2021 6:53 PM

Something that used to be common advice in the early days of LEDs was to take a battery with low nominal voltage (1.3V or under)... it can be old with voltage sagging, that's even better... and small enough that it won't source a lot of current without the voltage sagging.  A typical small 'button' cell like a hearing-aid battery or 'coin cell' fulfills these conditions nicely.  Test the LED by just connecting across the battery in the correct polarity if the rated voltage is higher than the cell's -- easy, portable, requires no meter and can be done easily in the dark or up under the layout easily.

If more modern or lower-voltage tiny LEDs or cores have come along for nominally ultra-low voltage use, you can put one of these cells in a holder with resistors on one lead, and test with that as a 'unit'.

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Posted by wolfman hal on Tuesday, October 19, 2021 7:25 PM

The thing is Greg that there is another 20 Switches wired the same way and they have been working for years

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Posted by gregc on Tuesday, October 19, 2021 7:48 PM

wolfman hal
The thing is Greg that there is another 20 Switches wired the same way and they have been working for years

so you're description must be wrong

greg - Philadelphia & Reading / Reading

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Posted by wolfman hal on Wednesday, October 20, 2021 7:12 AM

I will double check again and let you know.

I will be out of town for a couple of days so please check back .

Thanks

Harold

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Posted by richhotrain on Wednesday, October 20, 2021 8:18 AM

For those of us following this thread who are not experts on LED functionality, it sures seems like there must be a simpler way for the OP to deal with this issue.

For starters, why not just use a 2-leg bi-polar (red/green) LED instead of separate red and green LEDs?

What I do on my control panels is to attach a resistored bi-polar LED to the two center tabs on a DPDT. I have never had an LED burn out using this approach, so I am at 17 years and counting since first installing these LEDs.

Also, the OP's initial question remains unanswered. He has 10 vdc from the power supply to both ends of the DPDT, but no power from the output side of the DPDT to the Tortoise. What is the problem?

Rich

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Posted by wolfman hal on Wednesday, October 20, 2021 9:03 AM

Exact wiring

Ok hear is the layout.

6 position DPDT Toggle

2. 10 VDC to bottom postions Call 1 & 2

3. Criss Cross wires to 5 & 6  Top

4. Anode of Red  LED connected to Cathode of Green LED

5  Anode of Green LED connected to Cathode of Red LED

6.Center of connection of Red- Green LED to Pin #3 of switch

7. Center of connection of Green - Red LED to Tortoise Pin 8

8. Switch Pin # 4 to Pin #1 on Tortoise

Harold

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Posted by gregc on Wednesday, October 20, 2021 9:30 AM

wolfman hal
6 position DPDT Toggle

2. 10 VDC to bottom postions Call 1 & 2

3. Criss Cross wires to 5 & 6  Top

4. Anode of Red  LED connected to Cathode of Green LED

5  Anode of Green LED connected to Cathode of Red LED

6.Center of connection of Red- Green LED to Pin #3 of switch

7. Center of connection of Green - Red LED to Tortoise Pin 8

8. Switch Pin # 4 to Pin #1 on Tortoise

that description matches Mel's diagram, which is the recomended way to wire LEDs in series with a Tortoise machine.   do you agree the diagram matches your wiring?

 

in an earlier post you suggest the toggle switch can cause the machine to move the points in either position but neither LED works.   is this still true?

if true, suggests LEDs are shorted or there is insufficient current to light the LEDs.

did you say you have other machines wired up the same way and using the same LEDs?

 

 

 

greg - Philadelphia & Reading / Reading

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Posted by RR_Mel on Wednesday, October 20, 2021 12:44 PM

I got a new laptop and haven’t tried to make a CAD drawing so I decided to try it out.  This is what I came up with wired to your description.


Should work.

The description from Rich would also work very good




Also as Rich suggested a single two lead red/green bi-color LED would work in place of the separate red green LEDs.

Gota get a mouse for the laptop, drawing with the touchpad is a bummer.


Mel


 
My Model Railroad   
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Posted by CSX Robert on Wednesday, October 20, 2021 1:00 PM

In the earlier thread it was suggested that you bypass the LEDs to test the Tortoise.  If you did that, is the bypass still there?

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Posted by wolfman hal on Thursday, October 21, 2021 9:37 AM

Lets start with Greg

Mel's diagram does not match. I do not know if this matters but if you look at my notes DC power is connected to Pin #1  & Pin 2 and crisscrossed to 5 & 6 with LED connected to center pin. 

The Tortoise works. Only the LED's do not.

I know the circuit works as all my other Switch machines work properly.

The only reason that there are Red & Green LED's is that is what I did many years ago and if I changed this one it would leave a hole in my panel.

One thing I stated above is that these LED's come from a different source but I have been using them in different applications with no problem.

Let me Sumarize

1. Tortoise is working properly

2. Wiring is correct ( Anode of 1 LED to Cathode of the other LED )

3. Wiring is the same as 20 working Switch Machines

4. I have tried the hearing aid battery with no positive result . I also tried one on my bench with no result

5. By Pass is no longer in circuit

6. ( Problem ) Both Red & Green LED's do not light when Toggle is thrown.

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Posted by CSX Robert on Thursday, October 21, 2021 10:07 AM

wolfman hal
Mel's diagram does not match. I do not know if this matters but if you look at my notes DC power is connected to Pin #1  & Pin 2 and crisscrossed to 5 & 6

No, as I mentined before, that does not matter.

Try different LEDs.  If one of them is bad and is causing a short then neither one will light and the switch machine will still work.

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Posted by RR_Mel on Thursday, October 21, 2021 10:18 AM

If this doesn’t work then the LEDs are bad



Mel

 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
Just turned 84, aging is definitely not for wimps.

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Posted by richhotrain on Thursday, October 21, 2021 10:24 AM

wolfman hal

2. Wiring is correct ( Anode of 1 LED to Cathode of the other LED )

Are you sure your orientation is correct, anode to cathode, cathode to anode?

I always identify the anode (+) by spotting the smaller piece of metal inside the LED bulb.

If you decide to test those two LEDs, turn off power and connect a 1.5 volt battery to the two legs of one of the LEDs to see if it lights. Then, do the same to the other LED. If an LED does not light with the battery test, reverse the two wires from the battery and test again, just to be sure.

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Posted by Overmod on Friday, October 22, 2021 10:46 AM

richhotrain
wolfman hal

2. Wiring is correct (Anode of 1 LED to Cathode of the other LED)

Are you sure your orientation is correct, anode to cathode, cathode to anode?

I always identify the anode (+) by spotting the smaller piece of metal inside the LED bulb.

This is sage advice, but TMI for what he did.

'Anode to cathode' for the two devices is a bit like I2R losses in that all he had to do was to join the two devices 'opposite' (using your illustration as a guide).

When he has done that, testing with the 1.5V source (or the coin cell trick, etc.) is immediate, quick and definitive -- assuming he confirms the voltage is good with a meter or known-good light.

He puts power on it with one polarity -- one of the two LEDs lights.  He reverses wires and the other one lights.  If either or both stay dark... they're likely lunched.  (If you're a nerd like me you put an ammeter in series to verify electrical current is flowing; this is NOT Mel's test where he uses the slight test current of a multimeter on 'ohms' resistance setting to light the device...)

Then the way he wires this to the Tortoise determines what color comes on when you run it one way or the other.  If that is wrong just reverse leads going to the cathode-to-anode assembly.

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Posted by SpaceMouse on Friday, October 22, 2021 2:05 PM

I don't know whether the OP has actually done this, but I didn't see the answer in the thread.

Have you tested the LEDs? You say they are from a different supplier. Could they be defective or have lower resistance to current and require a resistor that the other 40 don't require. 

Using an AA battery to test the LEDs like Overmod suggest seems like an obvious next step. You can do it right on your layout. 

 

Chip

Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.

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