1.1 Sensor Excitation

Some sensors require an external excitation source to transform physical properties or entities into electrical signals, such as resistor-based sensors (thermistors, RTDs) and strain gauges. These sensors require current or voltage source for excitation to produce an electrical output. The accuracy in measurement of the sensor output depends upon the applied excitation. In noisy environments, current excitation is generally preferred due to its better noise immunity. Figure 1-2 shows a constant current excitation to a resistor bridge type sensor.