What is parasitic capacitance, parasitic inductance, parasitic effect,stray capacitan

Dear Sir,
What is parasitic capacitance, parasitic inductance,stray inductance, stray capacitance, parasitic effect, parasitic model.
can you explain me in detail, when we have to take account above parameters and when above parameter come into the picture in the RF & Microwave Circuit Design.
Can you give idea about these parameters.

raju_kambar said:

Dear Sir,
What is parasitic capacitance, parasitic inductance,stray inductance, stray capacitance, parasitic effect, parasitic model.
can you explain me in detail, when we have to take account above parameters and when above parameter come into the picture in the RF & Microwave Circuit Design.
Can you give idea about these parameters.

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The words "stray" and "parasitic" are often equal in meaning. Ideal components like capacitors and inductors can have their values calculated from their geometry and material properties. As they are located in real environment, nearby conductors and dielectrics like other components or walls add the stray and parasitic additions to calculated or ideally measured parameters. Those additions increase in importance with the growing frequency.

jiripolivka said:

As they are located in real environment, nearby conductors and dielectrics like other components or walls add the stray and parasitic additions to calculated or ideally measured parameters.

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Dear Sir,
Thank for your answer, I agree with you about the Capacitor nearby conductors and dielectrics,it gets parasitic effect. But what about inductor, inductor is device which opposes the change in current through it. How inductor will be effected by the nearby conductor and dielectrics and why it is called inductive parasitic effect. Will you clear it.

raju_kambar said:

Dear Sir,
Thank for your answer, I agree with you about the Capacitor nearby conductors and dielectrics,it gets parasitic effect. But what about inductor, inductor is device which opposes the change in current through it. How inductor will be effected by the nearby conductor and dielectrics and why it is called inductive parasitic effect. Will you clear it.

Click to expand...

I can see you understand the stray capacitance. Inductors generate magnetic field and this "opposes" the current as you wrote. Around the coil the magnetic field can couple to nearby conductors and generate eddy currents in them. Magnetic objects with a permeability can add to the coil inductance while close conductors often reduce coil inductance.
Ideal components should be tested far from any objects, then by installing them in a real environment we can see changes in their parameters. Such effects are called "stray".

raju_kambar said:

But what about inductori

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Main parasitic effects of SMD inductors are series resistance and parallel capacitance (from capacitance between the turns).

I think that "parasitic" means that the unwanted element is incorporated into the device, while "stray" is the result of actually using it. i.e. an inductor would have intrinsic interwinding capacity (parasitic), but if wired in with long leads would have additional "stray " interwinding capacitance.
Frank

chuckey said:

I think that "parasitic" means that the unwanted element is incorporated into the device, while "stray" is the result of actually using it. i.e. an inductor would have intrinsic interwinding capacity (parasitic), but if wired in with long leads would have additional "stray " interwinding capacitance.
Frank

Click to expand...

Yeah, that's a better description
I have always looked at parasitic .... as from within a device ... resistor, cap, inductor, semiconductor
where as stray .... is from say inductance/capacitance between adjacent PCB tracks, cable wires etc ( more to do with the "mechanical" layout of a circuit)

Dave