Date   
Re: Terminating bus ends

brianw1138@...
 

Power is an odd beast and is governed by I^2R .
In Series, I remains constant, but you break up your R (in series Resistance is addative), and therefore your voltage drop. You can arrive at the same result using Ohm's law, but it takes more steps; I think I^2 R is more illustrative. Just remember there is teh over all R and the individual Rs....

But the same applies in Parrallel (power-wise), but for different reasons. With parallel Resistance you need to work out the parrallel resistance formula, then ratio the current through the individual resistors, then apply I^2 R. For similarly sized components, each carries half the current.

Basically, In series, for similarly size resistors, each carries the same current, but has a lower voltage drop (each device has half the drop). Whereas in parallel, each device carries half the current, but at the same voltage drop.

That may seem confusing, but believe me, it's based on actual math. As my professors used to say: The proof is left as an exercise for the student!

Does this help?

Re: Terminating bus ends

kdkalit <kenkal@...>
 

Mark, shouldn't that read .....1/2W 390Ohm resistors in "parallel"?
I thought wattages are additive in parallel and resistance is
additive in series? Or am I all mixed up?
Ken

--- In WiringForDCC@..., Mark Gurries <gurriesm@c...>
wrote:

You can always use a series string of resistors to spread out the
heat.
Example: you could use 3 1/2W 39Ohm resistors in series. That
will give
you a long 117 ohm 1.5W resistor. The resistance accuracy is not
the
critical.

--- In WiringForDCC@..., "beckemeier53221"
<MBeckemeier@w...> wrote:
Thanks for the info Mike. I had already decided to use a 2 watt,
now I'll probably go with the 3 as you used.

Thanks for the info. Ken

I can attest to the resistors getting toasty. I had to install
over 90
of them on our club layout. Even the 1 watt resistor got quite
hot.

I eventually went with a 3 watt 130 ohm resistor and a 0.1uf 50
V
Capacitor. It really cleaned up the signal nice, and is not as
hot
to
the touch.

Capacitor:
Newark Part Number: 08B5602 Manufacturer Part Number:
C317C104M5U5CA.
Resistor:
Newark Part Number: 94C3740 Manufacturer Part Number :
5093NW130R0J

Mike Beckemeier






http://www.WiringForDCC.com
Yahoo! Groups Links





Best Regards,

Mark Gurries
Linear Technology
Power Supply & Battery Charger Applications Engineer/Manager
---------------------------------------------------------
Model Railroad Club and NMRA DCC presentations are at:
http://www.siliconvalleylines.com/index.html
--------------------------------------------------------
Audio Enthusiast (Love SAE equipment)
http://members.ebay.com/aboutme/gurriesm/
----------------------------------------------------------

Re: Terminating bus ends

kdkalit <kenkal@...>
 

Mark, shouldn't that read .....1/2W 390Ohm resistors in "parallel"?
I thought wattages are additive in parallel and resistance is
additive in series? Or am I all mixed up?
Ken

--- In WiringForDCC@..., Mark Gurries <gurriesm@c...>
wrote:

You can always use a series string of resistors to spread out the
heat.
Example: you could use 3 1/2W 39Ohm resistors in series. That
will give
you a long 117 ohm 1.5W resistor. The resistance accuracy is not
the
critical.

--- In WiringForDCC@..., "beckemeier53221"
<MBeckemeier@w...> wrote:
Thanks for the info Mike. I had already decided to use a 2 watt,
now I'll probably go with the 3 as you used.

Thanks for the info. Ken

I can attest to the resistors getting toasty. I had to install
over 90
of them on our club layout. Even the 1 watt resistor got quite
hot.

I eventually went with a 3 watt 130 ohm resistor and a 0.1uf 50
V
Capacitor. It really cleaned up the signal nice, and is not as
hot
to
the touch.

Capacitor:
Newark Part Number: 08B5602 Manufacturer Part Number:
C317C104M5U5CA.
Resistor:
Newark Part Number: 94C3740 Manufacturer Part Number :
5093NW130R0J

Mike Beckemeier






http://www.WiringForDCC.com
Yahoo! Groups Links





Best Regards,

Mark Gurries
Linear Technology
Power Supply & Battery Charger Applications Engineer/Manager
---------------------------------------------------------
Model Railroad Club and NMRA DCC presentations are at:
http://www.siliconvalleylines.com/index.html
--------------------------------------------------------
Audio Enthusiast (Love SAE equipment)
http://members.ebay.com/aboutme/gurriesm/
----------------------------------------------------------

Re: Terminating bus ends

Mark Gurries
 

Do not use wirewound resistors. They will actually make things worse!

Hot is a relative term. Power resistors normally are hot to the touch.
There is nothing wrong with using larger resistors if your goal is to
reduce any discomfort you have in working with them or coming into
contact with them. But it not required. There is not enough power to
cause any fire hazard or burn.

You can always use a series string of resistors to spread out the heat.
Example: you could use 3 1/2W 39Ohm resistors in series. That will give
you a long 117 ohm 1.5W resistor. The resistance accuracy is not the
critical.

--- In WiringForDCC@..., "beckemeier53221"
<MBeckemeier@w...> wrote:
Thanks for the info Mike. I had already decided to use a 2 watt,
now I'll probably go with the 3 as you used.

Thanks for the info. Ken

I can attest to the resistors getting toasty. I had to install
over 90
of them on our club layout. Even the 1 watt resistor got quite hot.

I eventually went with a 3 watt 130 ohm resistor and a 0.1uf 50 V
Capacitor. It really cleaned up the signal nice, and is not as hot
to
the touch.

Capacitor:
Newark Part Number: 08B5602 Manufacturer Part Number:
C317C104M5U5CA.
Resistor:
Newark Part Number: 94C3740 Manufacturer Part Number :
5093NW130R0J

Mike Beckemeier






http://www.WiringForDCC.com
Yahoo! Groups Links





Best Regards,

Mark Gurries
Linear Technology
Power Supply & Battery Charger Applications Engineer/Manager
---------------------------------------------------------
Model Railroad Club and NMRA DCC presentations are at:
http://www.siliconvalleylines.com/index.html
--------------------------------------------------------
Audio Enthusiast (Love SAE equipment)
http://members.ebay.com/aboutme/gurriesm/
----------------------------------------------------------

Re: Reversing section advice

Vollrath, Don <dvollrath@...>
 

Blair, One more thought.
If some of your track is hidden, it one more reason for making track polarity reversals and switch controls occur automatically. For example: a train exiting out of loop L should automatically throw SW2 as it approaches the exit...and correct the track polarity of L to match. If you can't see the train, it will be difficult if not impossible to throw toggle switches manually to do the job. There is an example of how to do this using an auto-reverser and relay at http://www.wiringfordcc.com/sw_ctl.htm#a16
DonV

-----Original Message-----
From: WiringForDCC@...
[mailto:WiringForDCC@...]On Behalf Of Rasa and Blair Smith
Sent: Wednesday, November 16, 2005 7:28 PM
To: WiringForDCC@...
Subject: RE: [WiringForDCC] Reversing section advice
<U said>
The flawless performance of this hidden trackage is important to me, as it
will be central to the operation of both my main line and one of the two
primary interchange railroads on my layout.

Re: Thinking switches.......

Vollrath, Don <dvollrath@...>
 

Reread Allan's ideas on DCC friendly switches at the link listed below. The bane of DCC is poor electrical connections and occasional short circuits can cause problems. Yes, you will want all rails energized.
I'm not familiar with Fleishmann-Profi products. I like Atlas cd 83 switches, but add wire bonding connections. The new DCC friendly switches from Walthers also look good as long as you add bonding wires and use an external microswitch to provide supplemental power to the frog.
DonV

Re: Reversing section advice

Vollrath, Don <dvollrath@...>
 

Blair,
My solutions 2 and 3 using relays do not have any real drawbacks. You simply add more insulating rail gaps in the appropriate places and wire up a DPDT relay(s) to control power to those sections of track. If you use Tortoise switch machines for turnout control this is simple to do. [Wire a 12Vdc relay coil in parallel with the Tortoise motor, but add a diode so that the relay coil gets energized with the tortoise in only one direction.] If you plan on using manual throws, add a DPDT toggle sw to do the same thing manually. Small electromechanical relays and toggle switch contacts change state in milliseconds. Any sound decoders on your locos won't even notice that track polarity has changed. Slide switches or 2 separate SPDT contact sets or microswitches or the contacts internal to a Tortoise may interrupt track power momentarily causing an annoying re-start of loco movement or sound. The advantage of using a relay is that the cost of relay or two is far less than any Auto-Reverser. Loy's ARSC is ~$80 USD.

Solution 1 with the Loy's toys ARSC may not be totally workable as your own words indicate that track section Y space may be slightly too short. It needs to be longer than the active wheelbase of your longest loco consist PLUS about 2 more inches at each end for what L-T calls portals. Each of these need to be slightly longer than a 3 axle passenger truck, but no longer. See my short track reverser explanations in the files section of this forum.

One other comment - For almost any A-R units, You may have difficulty starting up your DCC system if locos are bridging the isolating gaps at a reversing section of track. This occurs because the polarity detecting mechanism needs power to select the proper state and there is no power until the booster gets going. But if there is an instant track short on power up, the booster can't provide power to the relay or A-R unit for self correction...Catch 22. A manual toggle switch system, or one using a separate power source for relays can avoid this problem. A simple way is to simply avoid leaving locos bridging A-R rail gaps when you suspend operations.

DonV

-----Original Message-----
From: WiringForDCC@...
[mailto:WiringForDCC@...]On Behalf Of Rasa and Blair Smith
Sent: Wednesday, November 16, 2005 7:28 PM
To: WiringForDCC@...
Subject: RE: [WiringForDCC] Reversing section advice


Hello Don
Thanks for the informative and very useful response; yes the explanations
are excellent. As an electronics tech, everything makes sense. Your
comments about relays (and switches) make me think that although that will
accomplish what I want electrically, I will pay an unacceptable price in
performance if the train is visible. Since the reversing section trackage
in question is all staging, however, I wonder if I will even notice a
stagger, if that is the only effect. Are there other drawbacks you can
identify to solutions 2 and 3? Regardless, I am extremely interested in
your offer of more data in solution number 1, as my section Y is only longer
by about one inch than my longest conceived locomotive consist; the power on
my longest lighted passenger train would be shorter, but some of the long
freights will likely be 4 SD40-2 units, which fit with an inch to spare.
The flawless performance of this hidden trackage is important to me, as it
will be central to the operation of both my main line and one of the two
primary interchange railroads on my layout.
Regards
Blair Smith

Re: Terminating bus ends

Ken <kenkal@...>
 

--- In WiringForDCC@..., "beckemeier53221"
<MBeckemeier@w...> wrote:
Thanks for the info Mike. I had already decided to use a 2 watt,
now I'll probably go with the 3 as you used.

Thanks for the info. Ken

I can attest to the resistors getting toasty. I had to install
over 90
of them on our club layout. Even the 1 watt resistor got quite hot.

I eventually went with a 3 watt 130 ohm resistor and a 0.1uf 50 V
Capacitor. It really cleaned up the signal nice, and is not as hot
to
the touch.

Capacitor:
Newark Part Number: 08B5602 Manufacturer Part Number:
C317C104M5U5CA.
Resistor:
Newark Part Number: 94C3740 Manufacturer Part Number :
5093NW130R0J

Mike Beckemeier

Re: Terminating bus ends

Ken <kenkal@...>
 

--- In WiringForDCC@..., "beckemeier53221"
<MBeckemeier@w...> wrote:
Thanks for the info Mike. I had already decided to use a 2 watt,
now I'll probably go with the 3 as you used.

Thanks for the info. Ken

I can attest to the resistors getting toasty. I had to install
over 90
of them on our club layout. Even the 1 watt resistor got quite hot.

I eventually went with a 3 watt 130 ohm resistor and a 0.1uf 50 V
Capacitor. It really cleaned up the signal nice, and is not as hot
to
the touch.

Capacitor:
Newark Part Number: 08B5602 Manufacturer Part Number:
C317C104M5U5CA.
Resistor:
Newark Part Number: 94C3740 Manufacturer Part Number :
5093NW130R0J

Mike Beckemeier

Re: Terminating bus ends

Michael Beckemeier
 

Regarding the values of the Resistor and Capacitor:
I can attest to the resistors getting toasty. I had to install over 90
of them on our club layout. Even the 1 watt resistor got quite hot.

I eventually went with a 3 watt 130 ohm resistor and a 0.1uf 50 V
Capacitor. It really cleaned up the signal nice, and is not as hot to
the touch.

Capacitor:
Newark Part Number: 08B5602 Manufacturer Part Number: C317C104M5U5CA.
Resistor:
Newark Part Number: 94C3740 Manufacturer Part Number : 5093NW130R0J

Mike Beckemeier

If you wire your layout with the
booster near the center and multiple DCC buses fanning out like a
star, put an R/C terminator at the far end of each bus.

The particular type of capacitor doesn't matter much, as long as
it is non-polarized. Any 50V or higher mylar, ceramic,
polycarbonate, polystyrene or paper film type will all work OK.
However, do NOT use an electrolytic or tantalum type as they are not
rated for this type of duty and are very likely to be polarized.
For HO scale a 0.1 MFD capacitance value of just about any (+/-1, 2,
5, 10, or 20%) tolerance will work. And yes, do use a 100-150 ohm,
1 watt rated resistor. A 1/2 watt resistor will work, but it will
get hot...which reduces the lifetime.

DonV

Re: Reversing section advice

Blair & Rasa
 

Hello Don
Thanks for the informative and very useful response; yes the explanations
are excellent. As an electronics tech, everything makes sense. Your
comments about relays (and switches) make me think that although that will
accomplish what I want electrically, I will pay an unacceptable price in
performance if the train is visible. Since the reversing section trackage
in question is all staging, however, I wonder if I will even notice a
stagger, if that is the only effect. Are there other drawbacks you can
identify to solutions 2 and 3? Regardless, I am extremely interested in
your offer of more data in solution number 1, as my section Y is only longer
by about one inch than my longest conceived locomotive consist; the power on
my longest lighted passenger train would be shorter, but some of the long
freights will likely be 4 SD40-2 units, which fit with an inch to spare.
The flawless performance of this hidden trackage is important to me, as it
will be central to the operation of both my main line and one of the two
primary interchange railroads on my layout.
Regards
Blair Smith

Thinking switches.......

hhodina <hhodina@...>
 

Thank you for your reply,Don.What kind of switches will be best for HO-
DCC use.I'm presently using "Fleischmann-Profi"with motor &
ballast.Are switches,which have all rails energized,better for this
purpose? Thank you for any suggestion.

Re: Terminating bus ends

Vollrath, Don <dvollrath@...>
 

No offense taken and I agree. As originally stated it could be misinterpreted by someone who is trying to follow the directions written by someone else word for word. But then, I didn't write that. There is a learning opportunity here for everyone. Re-read what you print very carefully before you hit the send button. Try to understand how or why someone else might be confused by the wording you have chosen. Always write your questions and answers to be crystal clear. And for you readers...If there is something that seems confusing...Ask.

-----Original Message-----
From: WiringForDCC@...
[mailto:WiringForDCC@...]On Behalf Of Ken
Sent: Wednesday, November 16, 2005 1:49 PM
To: WiringForDCC@...
Subject: [WiringForDCC] Re: Terminating bus ends


Don, please don't take offense as I'm really not trying to be flip
here or play on semantics, but if the wording had indeed said one
per bus, I wouldn't have asked the question I did. But the wording
says "Yes, you will need two of these circuits for each bus - one at
each end."

To me, the key words are "two", "each" and "each" & that means if I
have one bus, it is a bus with two ends and the ends are dangling
and booster, and the wording states emphatically that each bus
requires two, not one. So to me, that means put one at the dangling
end and another at the booster end just like the wording said. And
since, with my limited DCC and electronic knowledge, it just didn't
sound right, it is why I posed my question.

But, I do thank you for the clarification. I really do appreciate
your taking the time to explain to a novice like myself.
Ken


--- In WiringForDCC@..., "Vollrath, Don"
<dvollrath@m...> wrote:

If someone tells you to put a nozzle at the end of your garden
hose, how many nozzles would you need? :-)

Technically the words should read "Connect an R/C terminator to
each DCC bus run at the end opposite from the booster." Do not put
a terminator at the booster. If you wire your layout with the
booster near the center and multiple DCC buses fanning out like a
star, put an R/C terminator at the far end of each bus.

The particular type of capacitor doesn't matter much, as long as
it is non-polarized. Any 50V or higher mylar, ceramic,
polycarbonate, polystyrene or paper film type will all work OK.
However, do NOT use an electrolytic or tantalum type as they are not
rated for this type of duty and are very likely to be polarized.
For HO scale a 0.1 MFD capacitance value of just about any (+/-1, 2,
5, 10, or 20%) tolerance will work. And yes, do use a 100-150 ohm,
1 watt rated resistor. A 1/2 watt resistor will work, but it will
get hot...which reduces the lifetime.

DonV






http://www.WiringForDCC.com
Yahoo! Groups Links

Re: Terminating bus ends

Ken <kenkal@...>
 

Thanks for the clarification, Brian. Ken

--- In WiringForDCC@..., brianw1138@c... wrote:

Ken,
I can address some of the terminology questions.

Re: Terminating bus ends

Ken <kenkal@...>
 

Don, please don't take offense as I'm really not trying to be flip
here or play on semantics, but if the wording had indeed said one
per bus, I wouldn't have asked the question I did. But the wording
says "Yes, you will need two of these circuits for each bus - one at
each end."

To me, the key words are "two", "each" and "each" & that means if I
have one bus, it is a bus with two ends and the ends are dangling
and booster, and the wording states emphatically that each bus
requires two, not one. So to me, that means put one at the dangling
end and another at the booster end just like the wording said. And
since, with my limited DCC and electronic knowledge, it just didn't
sound right, it is why I posed my question.

But, I do thank you for the clarification. I really do appreciate
your taking the time to explain to a novice like myself.
Ken


--- In WiringForDCC@..., "Vollrath, Don"
<dvollrath@m...> wrote:

If someone tells you to put a nozzle at the end of your garden
hose, how many nozzles would you need? :-)

Technically the words should read "Connect an R/C terminator to
each DCC bus run at the end opposite from the booster." Do not put
a terminator at the booster. If you wire your layout with the
booster near the center and multiple DCC buses fanning out like a
star, put an R/C terminator at the far end of each bus.

The particular type of capacitor doesn't matter much, as long as
it is non-polarized. Any 50V or higher mylar, ceramic,
polycarbonate, polystyrene or paper film type will all work OK.
However, do NOT use an electrolytic or tantalum type as they are not
rated for this type of duty and are very likely to be polarized.
For HO scale a 0.1 MFD capacitance value of just about any (+/-1, 2,
5, 10, or 20%) tolerance will work. And yes, do use a 100-150 ohm,
1 watt rated resistor. A 1/2 watt resistor will work, but it will
get hot...which reduces the lifetime.

DonV

Re: Reversing section advice

Vollrath, Don <dvollrath@...>
 

Oops.
My option 3 requires 2 A-R units and 1 relay.
DonV

-----Original Message-----
From: WiringForDCC@...
[mailto:WiringForDCC@...]On Behalf Of Vollrath, Don
Sent: Wednesday, November 16, 2005 11:06 AM
To: WiringForDCC@...
Subject: RE: [WiringForDCC] Reversing section advice


Hello Blair. I see 3 Options:

1. Use a standard A-R unit at loop L as you propose. Use Loy's Toys ARSC at section Y. This unit requires extra rail gaps but can handle trains that are longer than the reversing track section, as long as Y is longer than the powered loco consist. It does work, even with a long train of lighted passenger cars, but the location of rail gaps and their width are important, particularly on curves. I can send you more data if you are interested. I also have an improved version that you can build yourself for a lot less $$. Send me a private e-mail. [need 1 A-R unit, 1 Loy's Toys ARSC or equal]

2. Use a conventional A-R unit for track Y, but extend the effective length out to SW1, SW2 and X as you propose by use of a relay sensitive to throwbar position of SW1, only when it is set for track Y. SW1, SW2 & the track leading to X should always be at the same rail polarity as you have indicated. However, Loop L still exists, and it should be possible to pass a train from either side of L to Y through SW2 & SW1. But L itself is a reversing loop and it is not wise to connect two A-R controlled track sections end to end... so control the polarity of track L with yet another relay operated from the exit throwbar position of SW2, from the polarity of the SW2 track, which may be powered from the A-R unit of Y if SW1 is set that way. Photo sensors near SW2 can be used to automatically flip SW2 from either direction, but thats a whole 'nother matter. [1 A-R unit, 2 relays]

3. Use a standard A-R unit at track section Y and extend the effective length of isolated A-R track out into track A via a relay controlled by the throwbar at switch. The isolated extension into A must be long enough to hold an entire train. Leave tracks of SW1 & SW1 at the fixed polarity of B and B'. Use a 2nd standard A-R unit for track L. This can work, but you must also consider available track length of A beyond what is shown in your sketch. If it is long enough to avoid yet another complication of train length or passing restrictions this option may be easy to implement. [1 a-R unit, 1 relay]

With options 2 & 3, you must use DPDT relays (or toggle switches) to control rail polarity. DPDT contacts on most switch machines are break before make and can interrupt rail power on moving locos for too long of a time as throwbars change positions.

Are my explanations clear enough?

DonV



http://www.WiringForDCC.com
Yahoo! Groups Links

Re: Reversing section advice

Vollrath, Don <dvollrath@...>
 

Hello Blair. I see 3 Options:

1. Use a standard A-R unit at loop L as you propose. Use Loy's Toys ARSC at section Y. This unit requires extra rail gaps but can handle trains that are longer than the reversing track section, as long as Y is longer than the powered loco consist. It does work, even with a long train of lighted passenger cars, but the location of rail gaps and their width are important, particularly on curves. I can send you more data if you are interested. I also have an improved version that you can build yourself for a lot less $$. Send me a private e-mail. [need 1 A-R unit, 1 Loy's Toys ARSC or equal]

2. Use a conventional A-R unit for track Y, but extend the effective length out to SW1, SW2 and X as you propose by use of a relay sensitive to throwbar position of SW1, only when it is set for track Y. SW1, SW2 & the track leading to X should always be at the same rail polarity as you have indicated. However, Loop L still exists, and it should be possible to pass a train from either side of L to Y through SW2 & SW1. But L itself is a reversing loop and it is not wise to connect two A-R controlled track sections end to end... so control the polarity of track L with yet another relay operated from the exit throwbar position of SW2, from the polarity of the SW2 track, which may be powered from the A-R unit of Y if SW1 is set that way. Photo sensors near SW2 can be used to automatically flip SW2 from either direction, but thats a whole 'nother matter. [1 A-R unit, 2 relays]

3. Use a standard A-R unit at track section Y and extend the effective length of isolated A-R track out into track A via a relay controlled by the throwbar at switch. The isolated extension into A must be long enough to hold an entire train. Leave tracks of SW1 & SW1 at the fixed polarity of B and B'. Use a 2nd standard A-R unit for track L. This can work, but you must also consider available track length of A beyond what is shown in your sketch. If it is long enough to avoid yet another complication of train length or passing restrictions this option may be easy to implement. [1 a-R unit, 1 relay]

With options 2 & 3, you must use DPDT relays (or toggle switches) to control rail polarity. DPDT contacts on most switch machines are break before make and can interrupt rail power on moving locos for too long of a time as throwbars change positions.

Are my explanations clear enough?

DonV

Reversing section advice

Blair & Rasa
 

Hi folks
I've posted a sketch for a tricky bit of trackwork I have (it's in the files
section, called Reversing Sketch.pdf). Here's the accompanying text, and
questions.

Electrically, A, A', and A" are the same bus. B and B' could be the same
bus (and will be until Santa delivers a booster), or originate on a separate
one, but neither are expected to be reversing sections.

My original thinking was to put L, the reversing loop, on a PM42 reversing
section, and put the short segment at Y on another PM42 reversing section (Y
and L could actually be reversed by aux contacts on SW1 and SW2, but I
digress). The loop is long enough to hold my longest train (26'), but the
segment at Y is not (only long enough for a four-diesel consist). This
would not be a problem as I understand it, unless I were to run trains with
power requirements that are train-long, like lighted passenger consists.
Unfortunately, one of the signature trains expected to traverse from A to
A', and/or to traverse the loop, is the circa 1985 CP Canadian; two diesels
and a passenger car just won't do. Sigh. So back to the wiring plan.

My proposed solution for the problem is to make Y extend all the way to X,
including both 3-way switches. Alternatively, I could extend Y out through
A along the main line beyond A. Either solution means the reversing section
Y will see a lot of action, whereas I could see the original X not being
used very often.
Any other alternatives I'm missing?
Thanks in advance.
Blair Smith

Re: Terminating bus ends

Vollrath, Don <dvollrath@...>
 

If someone tells you to put a nozzle at the end of your garden hose, how many nozzles would you need? :-)

Technically the words should read "Connect an R/C terminator to each DCC bus run at the end opposite from the booster." Do not put a terminator at the booster. If you wire your layout with the booster near the center and multiple DCC buses fanning out like a star, put an R/C terminator at the far end of each bus.

The particular type of capacitor doesn't matter much, as long as it is non-polarized. Any 50V or higher mylar, ceramic, polycarbonate, polystyrene or paper film type will all work OK. However, do NOT use an electrolytic or tantalum type as they are not rated for this type of duty and are very likely to be polarized. For HO scale a 0.1 MFD capacitance value of just about any (+/-1, 2, 5, 10, or 20%) tolerance will work. And yes, do use a 100-150 ohm, 1 watt rated resistor. A 1/2 watt resistor will work, but it will get hot...which reduces the lifetime.

DonV

Re: Terminating bus ends

brianw1138@...
 

Ken,
I can address some of the terminology questions.

Some caps are polarized, they have a plus side and a minus side, these are usually marked in VDC (electrolytic and tantalums come to mind). Other caps aren't polarizied therefore they just get a working volts marking.

Caps are harder to make than are resistors, that's why the tolerance range is so wacky. If the cap says 10uf, believe it, unless you pulled the cap from another circuit it's probably OK, and still in tolerance. If your circuit doesn't work, meter it, and see if it's in tolerance. In general, if you have to make an adjustment, do it with the resistor, they are made in lots more sizes, just for this reason.

Hope this helps, and that they haven't changed the laws of Physics since I was in college!