Lonnie,
        I hate to say that it is not that easy, but, It is not that easy.

What you are referring to is called microstripping. The traces on a circuit board are based on trace capacitance vs.
trace impedance. The factors are, the distance between the traces, the thickness of the traces, the width of the traces,
the dielectric of the materials in the circuit boards, the SMBC, the conformal coating of the circuit boards, and so on.
You never just calculate for trace capacitance, because trace capacitance is based on trace impedance and trace
resistance, and become tuned circuits. Look for information on microstripping, I believe that you will find you answer
there. I personally spend considerable time in calculating and testing traces for resonate elements, that may help or
hurt the operation of my circuits.

Gordon Varney
www.iamnee.com


>
> Does anyone out there know of a formula for calculating the capacitance of
> circuit traces?
> I am using "standard 1 oz. thickness of copper" 6"X9" boards. (not sure
> what that comes to in actual thickness of copper)
> If we assume .006" spacing between traces how long of a trace would be
> required to create 20pf?
> There should be a formula for this if the thickness of the trace could be
> converted.
>
> KF4HAZ - Lonnie
>

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