Resistor is one of the most typically used passive components in electrical and electronics circuits. Resistor can be defined as a circuit element used for reducing current flow and also lower voltage levels in circuits. There are different types of resistors classified based on various criteria such as fixed value resistors,  wire wound resistors, metal film resistors and special resistors, which can be found in Microhm Electronics easily, the typical ones are respectively MMS series, EE series, HPMRY series and NSR series. The special purpose resistors can be listed as pencil resistors, light dependent resistors, force sensing resistors and so on.

 
Force sensing resistor can be defined as a special type of resistor whose resistance can be varied by varying the force or pressure applied to it. The FSR sensor technology was invented & patented by Franklin Eventoff in 1977. The FSR sensors are made of conductive polymer which has a property of changing its resistance based on the force applied to its surface. Hence, these are termed as FSR sensors, force sensing resistor is a combination of resistor and sensor technology.
 
The force sensing resistor is generally supplied as a polymer sheet or ink which is applied as screen printing. Both the electrically conducting and non-conducting particles are present on this sensing film. These particles are generally sub-micrometre sizes which are formulated for reducing the temperature dependence and also for improving mechanical properties, increasing surface durability.  
Even though there various types of force sensors, the force sensing resistors are having several advantages such as thin size (less than 0.5mm), very low cost and also good shock resistance. The only disadvantage of FSR sensors is low precision, there will be approximately 10% or more difference in measurement results.
 
Force sensing resistors are called as (PTF) polymer thick film devices. The resistance of FSR sensors decreases with increase in pressure applied to its surface.
 
Different types of resistors are utilized in diverse applications according to the circuit designed. Microhm Electronics prepare broad options for engineers' options.