F. H. Richardson's bluebook of projection (1935)

Record Details:

Title:
F. H. Richardson's bluebook of projection
Date:
1935
Publisher:
New York : Quigley Publishing Company, Inc.
Volume:
F. H. Richardson's bluebook of projection
Leaf #:
00037
Language:
English
Subjects:
Motion Pictures, Motion Picture Technology
Collection:
Books
Format:
Books
Contributor:
Media History Digital Library
Sponsor:
{"Media History Digital Library","Jeff Joseph"}
Coordinator:
Media History Digital Library
Description:
Date Added:
March 21, 2024
Something wrong or inaccurate about this page? Let us Know!

Thanks for helping us continually improve the quality of the Lantern search engine for all of our users! We have millions of scanned pages, so user reports are incredibly helpful for us to identify places where we can improve and update the metadata.

Please describe the issue below, and click "Submit" to send your comments to our team! If you'd prefer, you can also send us an email to mhdl@commarts.wisc.edu with your comments.




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.

ELECTRICAL ACTION 19 has been found that 50 or 60 cycle current is about as low as may be used for lighting without visible flicker in the light. Twice each cycle the voltage and amperage drops to zero, hence there is no light source energy and the only light available during that period comes from the lingering incandescence of the filament. At 60 cycles the action will be rapid enough to tide over without visible flicker. (62) On the other hand frequency as low as 25 cycles per second has very distinct advantages in the operation of motors. Frequencies lower than 25 are not suited for motors and poor for lighting. (63) Almost all commercial power plants which supply both power and light are producing 50 or 60 cycle current; where power is the chief requirement the frequency may be as low as 25. Figure 4 (64) (a) There is flicker in any light produced by a. c, no matter how rapid the cycle. At 60 cycles or higher, however, the action is so very rapid and the drop in illumination so slight that the human eye cannot discern it. (b) Each period of time between changes of direction is an alternation, (c) Two alternations are one cycle, (d) The voltage of a. c. may be raised higher or reduced to any desired point merely by causing the current to pass through a properly constructed trans