View Single Post
  #37   Report Post  
Posted to sci.electronics.repair
Michael A. Terrell Michael A. Terrell is offline
external usenet poster
 
Posts: 12,924
Default LED Series Christmas Lights


spamtrap1888 wrote:

On Jan 3, 6:05 pm, "Michael A. Terrell"
wrote:

Windmill wrote:
Long ago, magnetrons (of a different design from the ones still used in
microwave ovens) were the only way to generate high peak powers, and
the oscillation frequency of a magnetron wasn't very stable.


Not that they weren't stable. They were powered with unfilterd DC,
which caused a wideband output. They are operated as a self excited
oscllator when used in a microwave, and as long as the thisng is in
band, the frequency or bandwitch doesn't really matter. Have you ever
read the MIT Rad Lab series of declassified W.W.-II books, or Slotnik's
RADAR Handbook?


Isn't the frequency determined by the dimensions of the cavity the
energy is dumped into? Or does that tune it too broadly?



The dimensions are the largest part of determining the frequency, but
it can be 'pulled' by voltage. Since it isn't run in CW mode in a
microwave, the oscillation has to start each time the plate voltage is
high enough on the unfiltered DC supply. The magnetron is designed for
the application, to keep it operating in the assigned band in this mode
of operation.


--
You can't have a sense of humor, if you have no sense.