We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
38 MOTION PICTURE HANDBOOK post to which one wire is always attached. 2 is the binding post at the other end, 3, 4 and 5 being intermediate posts and A and B the wires. Now, if you attach to binding posts 1 and 2, you, of course, will see that the current must pass through the entire resistance, and you will thus be cutting down your cur- rent all you can with that machine. If, however, you were to attach a wire to binding post 3, connecting it with wire B. with a switch at X, you would "cut out" half of one coil when the switch was closed, since the current seeks the line of least resist- ance. If you attach in the same manner to binding post 4, with a switch at X, you cut out two whole coils when the switch is closed, but cut them in again (compel the current to pass through them), when it is again opened. If you attach in the same way to binding post 5 with a switch at X, you would cut out three coils when the switch is closed. I have sketched this out to show you that you may connect your wire anywhere, even in the center of a coil and cut in or out as much resistance as you desire; also to show you the principle on which the adjustable rheostats operate. B, Fig. 16, shows a type of rheostat often encountered. In this sketch we are looking down at the top ends of the coils. You will observe that the two rows of coils are connected at one end but not at the other, binding posts being placed at 1, 2 and 3. Now, if you connect your wires at 1 and 2, it will readily be seen that the coils are all placed in series and the current must pass through them all. If connection is made at 1 and 3, you will be using just half the machine, the other half being idle. If you connect at 1 and 3 and then connect binding posts 1 and 2 together with a piece of copper wire (jumper it is called) as per the dotted line, you will have placed two halves of the rheostat in multiple and will get approximately twice the amount of current you would get by the second- named connection. ri&j7 Right here let me explain the terms "series" and "multiple." This is something which confuses many, but which is, in reality, very simple. Series, as applied to rheostats, means that all cur-