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ronbryan · 17th Feb 2009, 10:58 am

John

A parallel resonant circuit is a low impedance off resonance and a high impedance at resonance. I would apply the AVO oscillator output across the parallel LC circuit via a 4.7k resistor, to prevent the low output impedance masking the resonant point. The scope probe should be connected across the LC circuit and you should observe a voltage maximum at resonance. The probe capacitance will affect the resonant frequency to some degree.

Ron

Apologies to Skywave for duplicated post.

17th Feb 2009, 10:58 am	#3
ronbryan Octode Join Date: Jan 2003 Location: Guildford, Surrey, UK. Posts: 1,959	Re: Measuring Resonant Frequency John A parallel resonant circuit is a low impedance off resonance and a high impedance at resonance. I would apply the AVO oscillator output across the parallel LC circuit via a 4.7k resistor, to prevent the low output impedance masking the resonant point. The scope probe should be connected across the LC circuit and you should observe a voltage maximum at resonance. The probe capacitance will affect the resonant frequency to some degree. Ron Apologies to Skywave for duplicated post.