Systems without internal amplification must receive supply voltage from an external source, and must send small signals (i.e., 30 mV) back to the amplifying source. What may start out as clean power can become degraded because of electrical noise between the excitation and the sensor.

A good sensor output may become distorted by the electrical noise as well. The internal amplifiers are housed in the same unit as the sensor. This ensures the power to the sensor and the signal amplification are accomplished inside the transducer.

This makes the system less vulnerable to electrical noise and creates a higher signal to noise ratio. The larger output also allows A/D converters to create a higher resolution output. Because the internal amplifiers are so close to the sensor, line drops in excitation are eliminated. The amplifier outputs are low impedance and internal amplifiers don’t contribute noticeably to system inaccuracy.

Internal amplifiers may not be feasible under certain conditions. Specifically, the circuitry in the amp cannot be subjected to extreme temperatures. If sensor placed in a location inaccessible to users (hazardous environment, small space, long distance), zero and span adjustments may not be able to be tweaked when needed. Internal amplifiers increase the overall size of the unit, which may be concern in some applications.