The BD-20 board from NCE will detect one district. You can see
the toroid in the photo (7).
Other manufacturers use these two basic themes. Once you
see the photo of each, you should be able to recognize which
design is being used, based on a photo of the board.
What resistor value?
Ideally, you want the highest resistance possible for your resis-
tive wheel sets, to keep the current draw to a minimum.
Digitrax says that it needs 10,000 ohms or less for positive
detection. So I’d recommend that value for all your wheel sets.
7
7: BD-20 detector board from NCE – photo courtesy NCE
Corporation.
