QUES: Initially PCBs were designed manually by creating a photomask on a clear mylar sheet, usually at two or four times the true size. Starting from the schematic diagram the component pin pads were laid out on the mylar and then traces were routed to connect the pads. Rub-on dry transfers of common component footprints increased efficiency. Traces were made with self-adhesive tape. Pre-printed non-reproducing grids on the mylar assisted in layout. To fabricate the board, the finished photomask was photolithographically reproduced onto a photoresist coating on the blank copper-clad boards.
Initially PCBs were designed mechanically how?

ANS: unanswerable

QUES: Compact Disc + Graphics is a special audio compact disc that contains graphics data in addition to the audio data on the disc. The disc can be played on a regular audio CD player, but when played on a special CD+G player, it can output a graphics signal (typically, the CD+G player is hooked up to a television set or a computer monitor); these graphics are almost exclusively used to display lyrics on a television set for karaoke performers to sing along with. The CD+G format takes advantage of the channels R through W. These six bits store the graphics information.
Why are CD-G players not useful for karaoke?

ANS: unanswerable

QUES: Ripple current is the AC component of an applied source (often a switched-mode power supply) whose frequency may be constant or varying. Ripple current causes heat to be generated within the capacitor due to the dielectric losses caused by the changing field strength together with the current flow across the slightly resistive supply lines or the electrolyte in the capacitor. The equivalent series resistance (ESR) is the amount of internal series resistance one would add to a perfect capacitor to model this. Some types of capacitors, primarily tantalum and aluminum electrolytic capacitors, as well as some film capacitors have a specified rating value for maximum ripple current.
What is another cause of dielectric losses in a capacitor?

ANS: current flow across the slightly resistive supply lines or the electrolyte

QUES: Other notable Old Etonians include scientists Robert Boyle, John Maynard Smith, J. B. S. Haldane, Stephen Wolfram and the 2012 Nobel Prize in Physiology or Medicine winner, John Gurdon; Beau Brummell; economists John Maynard Keynes and Richard Layard; Antarctic explorer Lawrence Oates; politician Alan Clark; entrepreneur, charity organiser and partner of Adele, Simon Konecki; cricket commentator Henry Blofeld; explorer Sir Ranulph Fiennes; adventurer Bear Grylls; composers Thomas Arne, George Butterworth, Roger Quilter, Frederick Septimus Kelly, Donald Tovey, Thomas Dunhill, Lord Berners, Victor Hely-Hutchinson, and Peter Warlock (Philip Heseltine); Hubert Parry, who wrote the song Jerusalem and the coronation anthem I was glad; and musicians Frank Turner and Humphrey Lyttelton.
In what year did Hubert Parry write the song Jerusalem?

ANS:
unanswerable