Description: Hysteresis is a phenomenon that refers to the dependence of a system on its previous history, meaning that the current state of the system not only depends on its current conditions but also on its past trajectory. This concept is especially relevant in the field of sensors and control systems, where readings can be affected by previous changes in the environment or in the system itself. In the context of electronic systems, hysteresis is used to avoid unwanted fluctuations in sensor readings, providing a more stable and predictable behavior. For example, in a temperature sensor, hysteresis can help prevent the system from constantly turning a fan on and off due to small temperature variations. By establishing an activation and deactivation range, more efficient control is achieved, and component wear is minimized. In summary, hysteresis is a key concept in the design of electronic and control systems, allowing for greater stability and reliability in practical applications.
History: The term ‘hysteresis’ comes from the Greek ‘hysteros’, meaning ‘delay’ or ‘difference’. Although the concept has been used in various disciplines, its application in physics and engineering became popular in the 19th century. One of the first to study hysteresis in magnetic materials was the English physicist James Clerk Maxwell in 1865. Over time, the concept has expanded to other fields, such as biology and economics, where systems can exhibit behaviors dependent on their history.
Uses: Hysteresis is used in a variety of applications, especially in control systems and sensors. In industrial automation, it is applied to prevent oscillations in process control, ensuring that systems operate more efficiently. In electronics, it is used in feedback circuits to stabilize outputs. It is also common in thermostats, where a temperature range is set to turn devices on or off, thus avoiding constant switching.
Examples: A practical example of hysteresis is using a temperature sensor to control a fan. If an activation temperature of 25°C and a deactivation temperature of 22°C are set, the fan will turn on when the temperature exceeds 25°C and will turn off when it drops to 22°C. This prevents the fan from constantly turning on and off due to small temperature fluctuations. Another example is using a water level sensor, where an activation and deactivation range can be set to avoid continuous operation of a pump.
