Chapter 8. 4.3V Powered Sensors
The NXT provides a DC voltage on the sensor input port for sensors that require a power supply. (The LEGO Light Sensors and Sound Sensors are examples of sensors powered this way.) It's defined as the 4.3V power supply, but the voltage actually varies about 7% with load. The plot in Figure 8-1 shows the voltage ranging from 4.6V, when the power supply is lightly loaded, to 4.0V when it's fully loaded. It is important to note that this plot is for the total current of all the ports put together.
Figure 8-1. 4.3V supply voltage versus current
Hall Effect Sensor
The Hall Effect Sensor describes a magnetic field phenomenon ...