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Detection circuit

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  • Member since
    October 2007
  • 126 posts
Detection circuit
Posted by southernpacificgs4 on Thursday, February 7, 2013 5:52 PM

Do some readers have simple  self made detection circuits, with a transitor and or diode for DCC?

In the output of the transitor(transitor must be able to switch) there must be a relais to activate the diode bridge for ABC.

And if you want to share them with me?

And some diode construction scheme to activate ABC braking?

  • Member since
    February 2002
  • From: Westchester NY
  • 1,747 posts
Posted by retsignalmtr on Thursday, February 7, 2013 6:35 PM

I use NCE BD-20 current detectors to detect trains for my signals and RR crossing flashers. I like them as they will operate 12 volt DPDT  DIP relays for the signals on my layout. They work with DC and DCC. They run about $12 per.

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Thursday, February 7, 2013 10:17 PM

Han Deloof has a 4 section diode-drop detector circuit on his site, you cna follow the schematic or buy the PC board to make them.

Rob Paisley has a current-transformer type detector circuit on his page. This operates similar to the BD-20.

I prefer the current transformer type circuits, since they don;t reduce running voltage to the track. With diode drop circuits, you get typically a 2-junction drop in voltage, so to prevent variations in speed, if you have undetected sections, they need to be fed through the same type of diodes, even if there is no additional detection circuitry.

                       --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    October 2007
  • 126 posts
Posted by southernpacificgs4 on Saturday, February 9, 2013 4:58 PM

Thank you for the info.

I have a question regarding the ABC if the power is routed through the diodes{5 needed)(needed to stop the loc in the stop section) giving asymetrical power, the train will stop in front of  a red signal but someone told me if you bypass 2 of the 5 the loc will slow down and pass the yellow signal with reduced speed. Is this correct?

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