The  frequency  of  the  oscillations  during  the  discharge  of  a  condenser  varies  inversely  as
the  square  root  of  the  product  obtained  in  multiplying  the  inductance  of  the  circuit  in  henries
by  the  capacity  in  farads,  or


N*  =


LC


If  L  be  converted  to  centimeters  and  C  to  microfarads,  the  formula  becomes  :
5,033,000


N  =


V  LC

As  an  example,  assume  that  the  condenser  C,  Fig.  95,  has  capacity  of  .001  microfarads  and
the  coil  L  inductance  of  25,000  centimeters  (or  25  microhenries)  then  the  frequency

5,033,000

N  = =  1,000,000  cycles  per  second  approximately.
V  25,000  X  -001

The  quotient  of  this  problem  does  not  imply  that  1,000,000  cycles  of  current  actually  took
place  in  one  second  but  that  during  the  period  of  oscillation,  the  condenser  discharged  through
the  inductance  at  this  rate.  It  must  be  remembered  that  the  condenser  is  being  charged  by  an
alternating  current  and  in  the  case  of  the  500  cycle  alternator  it  will  be  charged  1,000  times;
hence  in  one  second  there  are  a  number  of  idle  periods  during  which  the  condenser  receives  no
charge.
The  student  should  not  confuse  the  actual  number  of  oscillations  in  a  circuit  such  as  shown
in  Fig.  95  with  the  frequency  of  the  oscillations.  As  has  just  been  explained  the  oscillation

frequency  is  determined  by  the  dimensions
24000  CID5.  (inductance  and  capacity)  of  the  oscillatory
circuit  whereas  the  number  of  oscillations
per  single  spark  is  a  function  of  the  total
damping  of  the  circuit.  It  should  be  under-
stood that  an  oscillation  circuit  like  that  of
Fig.  95  if  charged  by  an  alternating  current
always  will  produce,  during  discharge,
oscillations  of  constantly  decreasing  ampli-
tude or  damped  oscillations.
A  circuit  like  that  of  Fig.  95  is
termed  a  circuit  of  radio-frequency.
