On 4 Dec 2006 14:13:15 -0800, "money"
wrote:

I have a circuit in which there is a series capacitance of value 680
pF. The characteristic impedance of the line is 50 ohms. Can any
suggest how do i plot the capacitance in the smith chart.

If suppoe it was a parallel capacitance, how do i do it?

I doubt this is a very effective communications channel for an
introduction to the Smith Chart, you need pictures.

Google for "smith chart tutorial", you will find plenty, and amongst
them you should find a suitable intro.

Owen
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