Linearization Circuit

A linearization circuit is a specialized electronic component used within a signal conditioning unit to process non-linear input signals from sensors such as thermocouples, RTDs, or pressure transducers. Its primary function is to transform these non-linear signals into linear output signals that are directly proportional to the measured physical quantity, thereby enabling precise measurement and control in industrial applications. The circuit typically employs operational amplifiers, resistors, and sometimes digital components to apply mathematical correction functions, including polynomial, logarithmic, or piecewise linear approximations, to compensate for the inherent non-linear characteristics of the sensor. This ensures that the output voltage or current varies linearly with the measured parameter, simplifying subsequent processing and display. The linearization circuit is designed to operate within specified electrical and environmental parameters. For instance, it accepts an input voltage of 24 V DC ±10% with reverse polarity protection, and provides a linearized output voltage range of 0–10 V DC. The accuracy, including linearity and hysteresis, is ±0.1% of full scale. It operates within a temperature range of -40 to 85 °C and can be stored at -55 to 125 °C, with non-condensing humidity up to 95% RH. The circuit is protected against dust and water jets, meeting IP65 per IEC 60529. It draws a supply current of ≤20 mA at 24 V DC, and requires a load resistance of ≥10 kΩ for voltage output. The response time for a 10–90% step is ≤10 ms. The housing dimensions are 100×60×25 mm, with mounting holes, and the weight is ≤150 g without cable. These specifications serve as reference ranges; users must verify model-specific values with the manufacturer. The linearization circuit is a passive component in the sense that it does not generate the measurement but conditions the signal for accurate interpretation. It is essential for applications requiring high precision, such as process control, automation, and data acquisition systems. When selecting a linearization circuit, consider the sensor type, input/output ranges, accuracy requirements, environmental conditions, and mechanical constraints. Always confirm the exact specifications and standards compliance with the legal manufacturer or supplier before procurement.

The linearization circuit operates by applying a correction function to the non-linear sensor signal. It uses operational amplifiers and resistor networks to implement polynomial, logarithmic, or piecewise linear approximations. The input signal is conditioned, amplified, and then shaped to produce an output that is linearly proportional to the measured quantity. Digital components may be used for more complex corrections. The circuit ensures that the output voltage or current changes linearly with the physical parameter, compensating for sensor non-linearity.