If you are playing an acoustic guitar, you don't have to have something like an acoustic guitar tuner. If you are using the line-in of the tuner, you only have to make sure the sound isn't clipping. It won't break down because of the signal of an acoustic guitar being stronger than that of an electric one.
In general, four types of guitar tuners are available. Clip-on tuners are placed at the guitar's headstock, and it measures the vibration frequency. Another type of tuner is the 'normal' one; a box which is a few inches in width, which inludes a line-in and a mic. They are cheap and versatile. The third category are the floor tuners. They don't have a mic, and lie on the floor of the stage. Mostly they do have a mute pedal. The most extensive tuners are the racktuners. They can be placed in a 19 inch rack, have a large screen and the expensive ones are very accurately.
This page was about the acoustic guitar tuner. As you have read, ever guitar tuner can handle an acoustic guitar.