connect the
same side
together,
either the
anodesor
cathodes.
Youmay
wish to
reviewmy
web site
for infor-
mationon
LED lights.
There
isa link tomyLEDcolumnnear thebottomof thatpage, too.
Thenyouconnect this junction (or thecommonone fora single
LED) througha resistor (1000ohmsat1/10wattor greater) to
the frog. Youconnect the twoother leads to the rails.Adjusting
which rail is connected towhichLEDwill achieve thedesired
colorwith the turnout thrown. See the schematicdiagram (5).
Besides its simplicity, this style of signaling shows for a
fact that the frog is actually connected to a specific rail.
Throwing the turnout shorts out one of the LEDs. So, if only
one LED is lit, you know there is physical and electrical con-
tact between one stock rail and the points. If both are lit,
the turnout is notmaking electrical contact, even if it is
physically in the correct position.
Is the block occupied?
Theothermajor reason for signals is to tell theengineer
whether theway forward is clear or not. Themost common
DCC ImpulsesColumn - 4
4: 4: Dwarf (pot) andmast mounted signal
on JimDuncan’s GM&O EasternDivision
inHO scale. JimDuncan photo.
4
setting iswhere there is a signal facingoutwardat eachbound-
aryof a signaled sectionof track. See (6, next page).
There are twoways todetect a train in the signaled section
of track:
Optical sensors thatwork forDCorDCC
DCCblockdetection (seemyAugust 2013 column:
.
Optical detectors areavailable inavailable-light and infrared
versions. Since theyarenot dependent uponDCC for their
operation, I’ll ventureaway from the strictlyDCC-relatedworld
and touchon thembriefly.Manymanufacturersoffer products
in this arena. A feware:
Azatrax
offers several products
Circuitronoffers theBD1
LogicRail Technology
hasseveralproducts
5: Schematic diagram of two LED signal for turnout posi-
tion using a live frog turnout it is easy to swapwires be-
tween the LED leads to achieve the desired signal.
5
MRH-Apr2014
