Home 
Search 
Today's Posts 
#1




Formula for Q of resonant circuit?
M J Dowden wrote:
I am trying to find the formula used to calculate the Q of a parallel RLC resonant circuit. There are a number of questions in the Amateur Extra test pool[1] that ask this and the formula that I have does not produce the correct answers. I have been using Q = (2 * Pi * f * L) / R, but the questions in section E5G of the test pool don't seem to work with that. The answers that are produced by that formula are among the "distracters," suggesting that I am making an obvious error that they expect some people to make. It's obvious that this formula for Q is not valid for a parallel RLCCircuit. If you let R go towards infinity, by this formula, the Q goes to zero, although it should obviously be infinite, since the circuit has no losses. The correct formula is Q = R / (2*pi*f*L) = R * 2*pi*f*C 73,  Fabian Kurz, DJ1YFK * Dresden, Germany * http://fkurz.net/ Online Log: http://dl0tud.tudresden.de/~dj1yfk/log.html 
Reply 
Thread Tools  Search this Thread 
Display Modes  


Similar Threads  
Thread  Forum  
Paralel resonant circuit tuning range calculator program.  Homebrew  
Formula for Q of resonant circuit?  General  
Formula for Q of resonant circuit?  Moderated  
Is there affordable software I can use to map out circuit traces for a printed circuit board?  Homebrew  
Resonant and Nonresonant Radials  Antenna 