DC-operated LVDTs are designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for general industrial use. DC-operated LVDT signal conditioners receive DC current or DC voltage as input signals. They excite a transducer according to defined parameters for voltage and frequency. A variable gain differential amplifier receives the resulting signal, which is then coupled to a synchronous detector, multi-step filter, analog-to-digital converter, and micro-controller. The DC-operated LVDT constructions have wide applications. The DC LVDT is provided with onboard oscillator, carrier amplifier, and demodulator circuitry for internally. Because of the presence of internal circuitry, the temperature limits of a DC LVDT typically range from -25 to +70 degree C. The major advantages of DC devices are the ease of installation, the ability to operate from dry cell batteries in remote locations and low system cost.