Sine Waves going to our telescope
Sine Waves going to our telescope
Light travels 186,000 miles per second. The wave length of light is .0005 millimeters. The speed of light divided by the wave length gives the frequency of light in hertz. The frequency of light in hertz is about 600,000,000,000,000 cycles per second.
Notes on the Sine Wave Java Applet
To make the display advance one 15 degree step press 'Stop' then 'Forward' once for each step. Pressing 'Reverse' decreases the degrees one 15 degree step at a time.
In 'Three Phase' mode the degrees always increase in 'Go' mode. In reverse the display will show two of the wires to the three phase motor have been reversed.
Various information about the Applet is shown on the browser 'Status' line, usually at the bottom left of the browser frame.
When the Applet begins there is a delay while the background pictures load. With the browser and ( rather slow ) computer I am using it takes some time for the pictures to load. If you want to reduce the picture load time you can edit a copy of this file in Notepad and change "4000" to what ever value you like. If you set the value too small the picture may not load at all.
<PARAM NAME=picture_load_time VALUE="4000" > <!-- milliseconds -->Pressing Go repeatedly ( six times ) in Three Phase mode will cause the milliseconds per cycle to be displayed. Notice that this value varies somewhat. If the computer is doing something else at the time the sine wave display is to be updated the update is delayed until the computer processor again returns to the Applet. A faster computer will probably reduce this fluctuation.
The control buttons are drawn from data stored in arrays in the computers memory. To see the contents of these arrays hold 'Shift' and press ? . To reset to normal press / . You will see a lot of flickering while viewing the button parameters. Normally an image that is to be displayed is first drawn in off screen memory. When the image is finished it is then displayed to the screen image.
Press 'Stop' more than six times to stop the sine wave image from updating the screen. Pressing 'Go' will cancel. Even with the sine wave update turned off the program should still update the background image now and then. If the Applet frame is moved off the edge of the browser frame then returned Applet's background will be blank until it updates itself.