Touchscreen lowdown -- Capacitive vs Resistive

Features Andrew Williams 15:56, 5 Jan 2010

We take a look at the two touchscreen types used on mobile phones, how they work and ask - which one should you buy?

If you’re after a new phone, there’s a good chance the one you wind up with will have a touchscreen. More and more often, new phones feature them these days, and if you’re on a higher-end contract, contact with them is virtually inescapable.

However, if you’re planning on giving into the touchscreen trend, there are a few important things to consider. The most important of these is that there are actually two types of touchscreen predominantly used in phones – resistive and capacitive. The experience of using the two is quite different, so we’d recommend getting clued up on the two technologies before taking the plunge in either direction.

How they work

The main reason they’re quite so different to use is that the way they register the presence of your finger and its prods are poles apart. Resistive technology works the way you might first imagine a touchscreen would function – it senses pressure.

The resistive touchscreen itself is made up of several layers, the topmost of which flexes under your finger or stylus, and is pushed back onto a layer behind it. This effectively completes a circuit, telling the phone which part of the screen is being pressed.

Capacitive touchscreens don’t rely on pressure, but rather they use electrodes to sense the conductive properties of objects, such as your finger. So, they don’t rely on having an object pressing particularly hard on their surface, but will only react to certain objects. Prod one with a standard stylus and you’ll get nowhere.

In Practice

Thanks to these core differences, the experience of using each type of touchscreen is almost instantly recognisable. The most famous phone of the last couple of years, Apple’s iPhone, uses a capacitive touchscreen, which helps to give the phone its ‘light touch’ interface.

As capacitive screens don’t need much contact at all, you can swipe across them very lightly and get just as good a response as you would with a slow, full-fingered drag. By comparison, the vast majority of resistive touchscreen phones won’t normally react at all to a very light swipe.

More recent resistive touchscreen phones, such as the Nokia N97, HTC Tattoo and Samsung Jet have made their resisitive touchscreens much more sensitive than those of previous years, helping to bridge the gap between the two technologies, but we’re yet to see a resistive touchscreen that convinced us it was capacitive for any length of time. Using a finger, capacitive screens will seem much more responsive.

So, it may sound like a capacitive touchscreen is the way to go, without any doubt, but things aren’t quite that simple – resistive touchscreens have their benefits too.

The simplest is that they don’t rely on the organic properties of your finger, so can be operated with just about anything – just not necessarily successfully. A more important plus point of resistive screens is that they offer more potential for accuracy.

If you try to operate a either sort of touchscreen phone with your finger, accuracy will fly out of the window, but use a resistive phone with a stylus and you’ll be able to get relative pinpoint accuracy.

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