HO / DCS / Variable Channel Question

DCS 4.30 allows variable channels top start at 0 and go up from 1 volt.

Thanks Stan and Barry

So on a DC variable I will need a bridge rectifier after the OUT TO TRACK on the DCS...

From what I seem to understand......a bridge rectifier are a combination of 4 diodes?

What would constitute a suitable bridge rectifier?

I have a number of IN4007 diodes on hand.

My DCS is 4.00

I'm a layman big time in this area......

Dave

Correct.  You can assemble your own bridge if you have 4 suitably sized diodes.  Google "bridge rectifier" for how-to or to be overwhelmed with an avalanche of information.

You need one that can handle the voltage and current of your HO setup.  Your 1N4007 diodes are 1000V and 1 Amp.  This might actually be enough for a small HO configuration but if going thru the hassle of wiring all this up, I'd look for a bridge rated at least 100V and 4 Amps which should handle most HO configurations.  For example, here's one on sale at Radio Shack for less than $1.

Well, you'll need to upgrade your TIU software to be able to go down to 0 Volts.  I don't recall exactly but I think otherwise the starting voltage was something like 5V.  In the past (before the software upgrade) guys using a bridge to drive DC loads could add series diodes to drop the voltage down to effect a lower starting voltage.

Stan

Thank You for your great information on this and my past project with the turbines.

I appreciate your clear and complete explanations.

Makes me think you either are or have been a teacher!

Again

Thank You

Dave

Hi Dave, sure thing - hope it works out.

Note that for direction reversal, most if not all guys using this method use a DPDT electrical switch (a few dollars) to manually swap the + and - bridge rectifier outputs before the track connection.  So you don't get simple remote direction control like variable-channel AC operation with O-gauge engines.

I suppose one could concoct some scheme to electronically swap the polarity of the bridge-rectifier output in response to some sequence of DCS remote button presses but I'm not aware of anyone having done so.