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I have no way to measure inductance.
To know what size Cap. you will need, you will have to have some idea of the inductance. One easy way to check the inductance uses an AC voltmeter a variable resistor (pot), and a low voltage 60 hz voltage source like a 120/12 volt transformer. Hook the inductance and the variable resistor in series. Apply the 60 hz source across the series combination. Adjust the pot until the voltage dropped across the pot and the inductance are equal. Read the value of the pot, this is now equal to the inductive reactance of the coil Xl plus that 18k DC resistance you said you measured. From this you should be able to calculate the approximate inductance of the coil, and the Capacitor value needed to tune it to 8 hz. Use L=(Xl+18k)/2*pi*60 and then 8^2=1/4*pi^2*L*C and solve for C. 73 Gary N4AST |
#2
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![]() "JGBOYLES" wrote in message ... I have no way to measure inductance. To know what size Cap. you will need, you will have to have some idea of the inductance. One easy way to check the inductance uses an AC voltmeter a variable resistor (pot), and a low voltage 60 hz voltage source like a 120/12 volt transformer. Hook the inductance and the variable resistor in series. Apply the 60 hz source across the series combination. Adjust the pot until the voltage dropped across the pot and the inductance are equal. Read the value of the pot, this is now equal to the inductive reactance of the coil Xl plus that 18k DC resistance you said you measured. From this you should be able to calculate the approximate inductance of the coil, and the Capacitor value needed to tune it to 8 hz. Use L=(Xl+18k)/2*pi*60 and then 8^2=1/4*pi^2*L*C and solve for C. 73 Gary N4AST Gary, This sounds like a good idea. Only thing I would worry about is that given the dimensions of the coil, it may be resonant below 60 Hz. Tam/WB2TT |
#3
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This sounds like a good idea. Only thing I would worry about is that given
the dimensions of the coil, it may be resonant below 60 Hz. Hi Tam, Well, guess you are right, the self resonant frequency of the coil may be below 60 hz and would make the measurements different, this compounds his problem. 73 Gary N4AST |
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