Principle purpose of this lecture is to present on Computer Output Device: Speakers. Computer speakers, or multimedia speakers, are external speakers, commonly equipped with a low-power internal amplifier. The standard audio connection is a 3.5 mm (1/8 inch) stereo jack plug often color-coded lime green (following the PC 99 standard) for computer sound cards. A few use an RCA connector for input. There are also USB speakers which are powered from the 5 volts at 200 milliamps provided by the USB port, allowing about 1-watt of output power.