crystal radio receiver 1921

Transcription

1 crystal radio receiver 1921

2 Projector Possibilities

3 Types of Projectors and Installation Liquid Crystal Display (LCD) Projectors Digital Light Processing (DLP) Projectors Liquid Crystal on Silicone (LCoS) Projectors The most mature multimedia projector technology is the LCD Review these projector technology description in the article Digital Projector Buying Guide.

4 Connecting Multimedia Projectors to your computer Set up your computer within reach of LCD projector cable. Set projector on stable, level platform. This platform should be approximately 10 feet from the projection screen. Make sure both the computer and projector are turned off. Notice that the lights on both machines are off.

5 Connections Connect VGA cable to back of computer and to "computer in" port on projector. The cable only connects one way. Don't force the connection. On the cable notice that one edge is longer than the other edge. Connect power cable to LCD projector. Turn on LCD projector. Press and hold down the "on" button on the projector or on the remote control. Listen for the fan running on the projector and notice the lights which indicate the projector is turned on.

6 Setting Up the Projector Turn on the computer. When the projector has warmed up sufficiently, you will notice the projector image outline on the projection screen. If the computer s window is not showing on the projection screen, you may have to use a toggle switch on your computer. On many Dell laptops, this switch is activated by holding down the Fn key while pressing the F8 function key. You may have to do this more than once. Using the projector control, ensure that you have selected the right input source: RGB or Computer 1,2, or 3 for computer input; or video for DVD input.

7 NEVER UNPLUG THE PROJECTOR WHEN ITS FAN IS RUNNING, JUST USE THE POWER BUTTON ON TOP TO TURN THE LAMP OFF. WHEN THE FAN STOPS IT IS SAFE TO TURN THE POWER OFF.

8 NEVER LEAVE ONE IMAGE PROJECTED FOR EXTREMELY LONG PERIODS. THIS MAY DAMAGE THE PROJECTOR S LENS.

9 The font size should be at least 28pt type to allow everyone in the room to read it. This text is 28pts

10 MULTIMEDIA PROJECTOR PORTS It is important to make sure your projector will accept data from all the primary sources you want to display. If you are using a VCR or DVD player then an S-Video input is a must. If you want to connect your school projector to external speakers, then audio output are important. If you want to use a computer with your projector, then RGB or Computer input is a must.

11 RGB Out or Computer Out Port Allows you to connect a separate external monitor to your projector, so the video from your computer can be seen on the projector and on a monitor at the same time

12 HDMI - Supports up to 1080p. Use for HDTV receivers, DVD/Blu-ray players, Media Center/Home theatre PCs. Highest digital video quality. Component-Video Supports up to 1080p -- Progressive-scan DVD players, set top boxes, game consoles

13 Audio In. Sends audio data from your computer, VCR or DVD player to the projector, so your audience can hear sound that's part of your presentation or video recording

14 Brightness Big rooms and big groups require big images. And that's big trouble if your light output (a.k.a. brightness) isn't strong enough to spread across a large area. Light output is measured in units called ANSI lumens. More lumens mean more brightness, and generally speaking, more brightness translates into bigger images that look good even when the lights are on in the room.

15 Brightness Depending on the lamp, lens optics, and projector design, ANSI lumens range from 200 to 10,000 per projector. The more lumens a projector has, the brighter the picture will be. Lumens lumens lumens lumens Application Use in rooms where the lights are off or their is low level ambient light. Use in rooms with some ambient light Use in rooms where the lights are on or there is a high level of ambient light.

16 How Long will the lamp last? A replacement lamp can cost an average of $500 and operate anywhere from one to two thousand hours. Find out from the vendor how many hours of peak brightness to expect, and the lamp s life expectancy. The number of hours of peak brightness is important because it is often less than the life expectancy.

17 What Resolution is needed Resolution means the number of pixels used by the projector to create an image. The greater the number of pixels per inch, the greater the resolution. Higher resolution means better image quality. Projector resolution then refers to rows and rows of small elements to make the image we see, that is, horizontal and vertical pixels. Most modern projectors have XGA resolution, which is represented as 1024 x 768 for a total of 768,432 pixels. An SXGA projector offers 1280 x 1024 or approximately 1.31 million pixels.

18 Projector Resolution 2 The resolution of the projector is further determined by the resolution information received from the computer to which the projector is attached. If you set your computer resolution to 800 x 600, and your projector is capable of processing 1024 x 768, the projected image will be 800 x 600. If you set your computer resolution to 1400 x 1050 and your projector is capable of processing 1024 x 768, the projected image will be 1024 x 768.

19 Projector Limitations and Pricing Limitations of multimedia projectors include: (1) the simultaneous projection of more than one image, (2) the direct projection of physical models, and (3) the projection of transparencies. The two biggest factors which affect the purchase price of a projector are resolution and brightness.

20 Contrast ratio Experts believe that the higher contrast ratios produce more gradients of gray, providing sharper edges and smoother reproductions of imaging challenges, such as shadows and clouds. Contrast ratio is the ratio between the brightest and darkest areas of an image. When maximized it gives the clearest image, and it is impacted by room light.

21 Aspect Ratio The standard analogue television screen ratio today is 1.33:1. The Aspect Ratio is the relationship between the width and height. A Ratio of 1.33:1 or 4:3 means that for every 4 units wide it is 3 units high (4 / 3 = 1.33).

22 Digital Television Aspect Ratio Movies shown in the cinema are filmed in a variety of large screen ratios, but the most common is Panavision 2.35:1. When these movies are shown on TV they do not appear the way they were shown in the cinema. This is because the TV aspect ratio is smaller than the ratios in the cinema, similar to that shown by the diagram above.

23 Digital Keystone Digital Keystone adjustment is used to correct geometry distortions such as a skewed trapezoidal image due to a hasty setup, uneven support, etc. (Digital Projector Buying Guide, p.8)

24 Throw Distance Throw distance determines where the projector will sit in your classroom relative to the projection screen for optimal viewing. For any given projector, the width of the image (W) relative to the throw distance (D) is known as the throw ratio D/W. So for example, the most common projector throw ratio is 2.0. This means that for each foot of image width, the projector needs to be 2 feet away or D/W = 2/1 = 2.0. So if I'm using a projector with a throw ratio of 2.0 and I have an image width of 5 feet, then my throw distance must be 10 feet.

25 Throw Distance

26 Sources: Images from LCD Projector Guide GuidesandTutorials.com Articles at course website The Truth about IWB Resolution The Journal, June 2002, retrieved 9/14/06