The BD-1 is bidirectional and will give proper indications even if a train leaves a block by reversing direction and backing out. The CIRCUITRON BD-1 also contains driver circuitry sufficient to power a pair of two-color LED (including 2 lead Bi-Color LEDs) or incandescent lamp block signals at each end of the protected block (LED-type signals must be wired with a common anode [+] configuration). The outputs on the BD-1 can control a maximum of 250 ma. For 3-color signaling, additional signal drivers will be necessary (see our SD-x series of drivers later in this section). The BD-1 requires a 10-18 volt DC input for proper operation. The power supply should be filtered for proper operation.

If you do not have a filtered power supply, the CIRCUITRON PS-1 filtered AC to DC Converter or PS-2 Regulated AC to DC Converter are ideal for this application. The BD-1 is constructed on a 2” x 3” printed circuit board.

The BD-1HD is identical to the BD-1 but includes heavy duty output transistors to power lamps in large scale signals. Each output on the BD-1HD can control 500 ma.