Piezoresistor is a kind of voltage limiting element which is sensitive to the change of voltage. Its characteristic is: at the specified temperature, when the voltage exceeds a certain critical value, its resistance value will decrease sharply, the current through it increases sharply, the voltage and current do not show a linear relationship.Therefore, varistors are also called nonlinear rheostors.

Piezoresistor is short for voltage sensitive resistor, it is a kind of nonlinear resistance element.The resistance of a piezoresistor is related to the voltage applied at both ends. When the voltage applied to the piezoresistor is within its nominal value, the resistance of the piezoresistor is infinite and almost no current passes through.When the voltage at either end of a piezoresistor is slightly higher than the nominal voltage, the piezoresistor quickly breaks through the conduction, and the resistance value drops quickly, leaving the resistor in the conduction state.When the voltage decreases below the nominal voltage, the resistance increases again and the piezoresistor returns to a high resistance state.When the voltage at either end of a piezoresistor exceeds its maximum voltage limit, it will completely break down and fail to recover itself.