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Old 17th Feb 2009, 10:23 am   #1
John M0GLN
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Join Date: Jan 2004
Location: Southport, Merseyside, UK.
Posts: 1,156
Default Measuring Resonant Frequency

I want to check that the approximate resonant frequency of a LC circuit I've got is about 7MHz, it consists of a home made coil in parallel with a variable capacitor, not having anything specific to use, i.e. dip meter, I connected the LC circuit to the output of an Avo oscillator, set it to 7MHz and connected the input of my 'scope to the other side of the circuit, by rotating the variable capacitor I get three definite points, at maximum and minimum capacitance the 'scope trace is maximum and when the capacitor is about halfway the trace goes to more or less a straight line, am I right in assuming this point is the resonant frequency, or am I making some basic errors, would anyone advise please?

John.
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