The difference between impact and non – impact printer is as follows:

Impact printer / Dot-matrix Printer

Non impact Printer / Laser Printer

1. It prints characters or images by striking print hammer or wheel against an inked ribbon. 1. It prints characters and images without striking the papers.
2. Its speed is slower. 2. Its speed is faster.
3. Its printing quality is lower. 3. Its printing quality is higher.
4. It normally uses continuous paper sheet. 4. Its normally uses individual paper sheet.
5. It generates noise during printing. 5. It does not generate noise during printing.
6. It uses inked ribbon for printing. 6. It uses toner or cartridge for painting.
7. It is less expensive. 7. It is more expensive.
8. Dot matrix is an impact printer. 8. Laser printer is a non-impact printer.


Q. what is the usage of plotters? Explain different types of plotters.

usage-of-plottersA plotter is an output device that is used to produce high quality graphics in a variety of colors. Plotters are used to create maps, architectural drawings, graphs and charts.

Types of Plotters

Different types of plotters are as follows:

. Flatbed plotter

. Drum Plotter

1. Flatbed Plotter

Flatbed plotter is used to plot of draw images. It contains pens for drawing images. The paper is places on table-like surface. Software instructs the pens to move down on the paper. The pen then moves on the paper for creating images. Most flatbed plotters have one or move pens of different colors and widths.

2. Drum plotter

Drum plotter uses a rotating drum or cylinder. The drawing pens are mounted on the drum. The pens move to the left and right as the drum rotates. This movement creates the desired image. The advantage of drum plotter is that the length of the plot is almost unlimited. The roll paper can be used to draw very lengthy images. The width of the image depends on the width of the drum.  (Figure: Drum Plotter)


Q. Which device is used to output audio data from the computer?

output-audio-data-from-the-computerA type of output produced in the form of sound, voice or music is known as audio output. Speakers and headsets are two commonly used audio output devices.

Many personal computers contain internal speaker. The quality of internal speakers is not very high. External speakers are used for high quality audio output. Some monitors also contain speakers on their sides.

Any person sitting near the computer can hear audio output of speaker. It may create disturbance for other. A variety of speakers are available in market. Headsets are also used to produce audio output. But only the person using headset can heat this sound.