The LED circuit is interrupted by a PNP transistor, which is controlled by the output of the hall effect sensor, so that they turn on when the hall effect turns off.

These hall effect sensors require a steady current to work, so they must be independently grounded to allow a small intentional leakage current, therefor the necessary circuits will be power to sensors, power to LEDs, ground from sensors, ground from LEDs, all separately. Again, any will do.īesides some wire bits, that's all you need. (1x) Protoboard, I used a 2x8cm with 2.54mm pitched holes. (1x) Switch, not really necessary, any will do, I had these lever microswitches on hand so I used them. (2x) PNP transistors, I used a 2N3906 because they're cheap and easy. I solved this problem by putting a small red sharpie mark on the bottom of the red LED. Note, if you use clear LEDs like I did, don't mix them up (like I did). (2x) LEDs, pick one for each color, I used red for north, and blue for south. (4x) 1k Resistors, I used 1/4W 1% metal film resistors, but it doesn't matter much. (2x) Y3144 Hall Effect Sensor, interchangable with A3144, A3141, and a couple others. In this condition, the base is directly connected to the ground.The parts required are as follows, and visible in the first picture: Similarly, in the cut-off region, it works as an open switch means both junctions will be reverse biased, and emitter-base voltage will be less than 5V thus transistor works as a fully open switch. In the saturation region, it works as close switch means both junctions will be forward biased, and emitter-base voltage will be greater than 5V thus transistor works as a fully closed switch. In the active region, it works as an amplifier means its emitter-base junction will be forward biased and the collector-base junction will be reversed biased.

Either it is used for switching or amplification it works in three modes of operation.

Collector emitter saturation voltage: 0.25Vįor further details download datasheet 2N3906 DataSheet Where and How to Use 2N3906 TransistorĢN3906 transistor is generally used for high-speed switching and amplification purpose.

Storage temperature range: -55 to 150C 0.

Minimum forward current transfer ratio: 100.

Junction operating temperature range: -55 to 150C 0.

Emitter pin is input pin used for basing the emitter base junctionīase pin is control pin used for controlling the emitter to collector current.Ĭollector pin is output pin used for providing current to the load.

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