11-08-2015, 05:25 PM
Example of L and C in series.
If, at a particular frequency (remember that reactance varies with frequency) the L is +6 ohms and C is -6 ohms they just add giving zero. This is series resonance, when the overall reactance of the tuned circuit falls to zero. If the frequency rises the inductive reactance will rise while the capcitative reactance will fall (towards zero). Hence the overall reactance will rise.
If you try the same trick for a parallel LC circuit and use the usual product divided by sum method you'll end up dividing by zero at the resonant frequency. In other words for an ideal L and C a parallel tuned circuit has infinite reactance at resonance.
If, at a particular frequency (remember that reactance varies with frequency) the L is +6 ohms and C is -6 ohms they just add giving zero. This is series resonance, when the overall reactance of the tuned circuit falls to zero. If the frequency rises the inductive reactance will rise while the capcitative reactance will fall (towards zero). Hence the overall reactance will rise.
If you try the same trick for a parallel LC circuit and use the usual product divided by sum method you'll end up dividing by zero at the resonant frequency. In other words for an ideal L and C a parallel tuned circuit has infinite reactance at resonance.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
