The Resistive consists of a normal glass panel that is covered with a conductive and a resistive metallic layer These two layers are held apart by spacers, and a scratch-resistant layer is placed on top of the whole setup. An electrical current runs through the two layers while the monitor is operational. When a user touches the screen, the two layers make contact in that exact spot. The change in the electrical field is noted and the coordinates of the point of contact are calculated by the computer. Once the coordinates are known, a special driver translates the touch into something that the operating system can understand, much as a computer mouse driver translates a mouse's movements into a click or a drag.
In the Compacitive, a layer that store electrical charge is place on the glass panel of the monitor. When a user touches the
monitor with his finger, some of the charge is transferred to the user, so the charge on the capacitive layer decreases. This decrease
is measured in circuits located at each corner of the monitor. The computer calculates, from the relative differences in charge at each
corner, exactly where the touch event took place and the relays that information to the touchscreen driver software. One advantage that
the capacitive system has over the resistive system is that it trasmits almost 90% of the light from the monitor, whereas the resistive
system only transmits about 75%. this gives the capacitive system a much clearer picture than the resistive system.
On the monitor of a Surface Acoustic Wave, tow transducers (one receiving and one sending) are placed along the X and Y axes of the monitor's glass plate. Also placed on the glass are reflectors - they reflect an electrical signal sent from one transducer to the other. The receiving transducer is able to tell if the wave has been disturbed by a touch event at any instant , and can locate it accordingly. The wave setup has no metallic layers on the screen, allowing for 100% light throughout and perfect image clarity. This makes the surface acoustic wave monitor the best for displaying detailed graphics (both other systems have significant degradation in clarity).
As far as price, the resistive system is the cheapest; it clarity is the lowest of the three, and its layers can be damaged by sharp objects. The surface acoustic wave setup is usually the most expensive.
POS For Less offers a wide variety of touchscreen monitors from these fine manufacturers -
POS for less
720-283-1352
fax - 720-283-1356
email - posforless@posforless.com