Twin-T Detection Circuit

Model Railroader Layouts and layout building
1

I have a copy of the 1974 publication “Electronic Projects For Model Railroaders”. On page 41 the "Twin-T " detection circuit is shown.

Does anyone have a 21st century version of this circuit? I am looking for something inexpensive that I can build quickly for 20 or so blocks, and that will work with DCC. Most of the commercial circuits I have seen are pretty expensive.

Thanks for your help.

2

I suspect that Circuitron has something similar or close to what Twin T accomplished.

The Signal Research firm has a system that seems all encompassing but thus far they have only offered a version with one throttle which I think is too limiting for me in spite of some enthusiastic users who have posted in this forum.
Dave Nelson

3

Thanks for the information Dave. . . However: Circuitron has two products. The most interesting is $16 and offers two block detection with built in signal drivers. I searched the internet for “Signal Research” but didn’t get any hits for anyting related to model railroading.

What I really want is a circuit diagram for just a detector, one I can build myself. I don’t need the signal drivers.

4

The 21st century version of the Twin T is Bruce Chubb’s Optimized Detector circuit (actually first published in the 1980s, but then the Twin T is from the 1950s!). See Bruce’s series on signaling beginning in the January MODEL RAILROADER. He also has a DCC version of the Optimized Detector using impedance detection to avoid interference with command signals. It was covered in the May 2000 MR, page 90.

Happy holidays,

Andy

5

Thank you Andy; I just went back and ordered the May 2000 issue.

6

Don, sounds like Andy has answered your question . Signal research is at www.signalresearch.com

Dave Nelson

7

Thanks! I’ve got all the info I need and I appreciate your help.

8

Check the TracTronics site. They are pretty good about posting up circuit diagrams.
And I know they have detection circuits.