There are three basic systems used to recognize a person's touch: Resistive Capacitive Surface The acoustic wave resistive system consists of a simple glass panel that is covered by a conductive and a resistive metal layer. These two layers are held apart by spacers , and a scratch resistant layer is placed on top of the whole setup. When activating the monitor an electric current passes through two layers. When a user touches the screen , two layers that communicate in the exact spot. Changes in the electric field are noted and the point of contact coordinates are calculated by the computer. Once the coordinates are known , a particular driver translates something that touches the operating system as much as a computer can understand by clicking the mouse driver or translates the movement of a mouse into a drag. In capacitive systems , a level monitor glass panel is placed that stores electrical charges. When a user touches the monitor with his or her finger , the charge is transferred to some user , so the charge on the capacitive level decreases. This reduction is measured in the circuit located at each corner of the monitor. The computer touch event then takes place and just where the relative differences in charge in each corner , the calculation that relays the information regarding the touch screen driver software. The advantage that the capacitive system has over the resistive system is that it transmits about 90 percent of the light that the resistive system transmits only 75 percent , since from the monitor. This capacitive system gives a much clearer picture than the resistive system. On a surface acoustic wave system , two transducers ( one receiving and one sending) are placed along the x and y axis of the monitor's glass plate . Also reflectors are placed on the glass - they reflect an electrical signal sent from one transducer to another. The receiving transducer cannot tell if the wave has been disturbed by any instantaneous one-touch event , and can detect it accordingly. The wave setup has no metallic layer on the screen , allowing for 100 percent light throughput and perfect image clarity . This makes the best surface acoustic wave system for displaying detailed graphics (both other systems have a significant deterioration in clarity). The difference in the system which will not be registered as a touch event of stimulation in other areas. Two-level contact , which does not matter if you touch it with your finger or a rubber ball , means that the resistive system registered a touch as long as to do. A capacitive system , on the other hand , registers a touch , so that usually your finger , must have a conductive input. The surface acoustic wave system works like many resistive systems , causing a touch with almost any object - except for hard and small objects like the tip of a pen. As far as value , resistive systems are contextual ; Its clarity is the lowest of the three , and its level can be damaged by sharp objects. Surface acoustic wave setup is usually the most expensive.