I normally call my adviser related to those doubts...he is travelling or busy to answer, this way i will open one question... a little bit ashamet related ignorance.
Lets suppose you assemble components in a turned up side down board.... i do this way... since i was a kid.
So, no conduction of eletrons because phenolic and fiber glass are very good insulators.
But, i glue them to ground metal chassis.... so i think capacitance will be created because off two pieces of metal 1 mm distance (may be 2 milimeters or something alike)... in audio amplifier,
may i expect some trouble?
Is it a good way to avoid oscilations?
Will this induce oscilations?
I suppose 1 picofarads, or half each point... can be helpfull or a problem.
Carlos
Lets suppose you assemble components in a turned up side down board.... i do this way... since i was a kid.
So, no conduction of eletrons because phenolic and fiber glass are very good insulators.
But, i glue them to ground metal chassis.... so i think capacitance will be created because off two pieces of metal 1 mm distance (may be 2 milimeters or something alike)... in audio amplifier,
may i expect some trouble?
Is it a good way to avoid oscilations?
Will this induce oscilations?
I suppose 1 picofarads, or half each point... can be helpfull or a problem.
Carlos
I really do not know
And sometimes, when ashamed i go straigth into a friend... he is too much busy.
This way i put here, because we have very special knowledge people that normally do not like to show themselves.... but always a chance to wake them up to help me!
Hugh from Aksa
Rodd is another
And there are more 10 i suppose that i could not discover them.
Carlos
And sometimes, when ashamed i go straigth into a friend... he is too much busy.
This way i put here, because we have very special knowledge people that normally do not like to show themselves.... but always a chance to wake them up to help me!
Hugh from Aksa
Rodd is another
And there are more 10 i suppose that i could not discover them.
Carlos
destroyer X said:
But, i glue them to ground metal chassis.... so i think capacitance will be created because off two pieces of metal 1 mm distance (may be 2 milimeters or something alike)...
Well, firstly, you are basically creating a capacitor from EVERY trace to GND.
So, thinking on the high side, lets say it's all hand soldered work, no PCB etching. In this way, I'll assume your traces are 3mm wide. We'll also use 1mm distance to Metal since that is the worse case number.
C = eo*A/d eo = permativity of air = 8.85 x 10 -12 F/m. A = area in meters^1, d = distance between plates in meters.
So, we can start with a particular length, say 1cm, and get a characteristic capacitance for every cm of trace which can be multiplied out for each trace.
So for 1cm of 3mm trace.
C = eo * .01*.003 / .001 = 2.655E-13. That is .27 pF.
1pf for each 4cm of trace about.
--
Danny
Hi Carlos, hi Azira,
please note that the capacitance will be higher, because the dielcetrical material is not air but phenolic.
The relative dielectricity constant of phenolic or bakelit ranges between
3.5 ....5 from what I know. So factor 4 may be a reasonable approximation.
Bye
Markus
please note that the capacitance will be higher, because the dielcetrical material is not air but phenolic.
The relative dielectricity constant of phenolic or bakelit ranges between
3.5 ....5 from what I know. So factor 4 may be a reasonable approximation.
Bye
Markus
Hello Azira and Chocoholic
Thank you...but nobody told me if this can be a problem or not.
This way i suppose so small capacitance will not make it oscilate because will ressonate in SHF frequencies.... and those transistors do not have response to oscilate... this way, this capacitance represents nothing?
Am i rigth.... that's what i was thinking, but full of doubts because i learn all by myself, this way... a lot of doubts, i cannot make those calculations and have those values to think about.
thank you all
Carlos are thinking that's no problem!
best regards
Carlos
Thank you...but nobody told me if this can be a problem or not.
This way i suppose so small capacitance will not make it oscilate because will ressonate in SHF frequencies.... and those transistors do not have response to oscilate... this way, this capacitance represents nothing?
Am i rigth.... that's what i was thinking, but full of doubts because i learn all by myself, this way... a lot of doubts, i cannot make those calculations and have those values to think about.
thank you all
Carlos are thinking that's no problem!
best regards
Carlos
...well, nobody can really answer how this will sound.
Regarding oscillations you can have positive or negative effects, depending on the entire setup .... also depending on which other
couplings between the metal and your circuit are existing...
may be connected to ground of your electronics... may be not....
Bye
Markus
Regarding oscillations you can have positive or negative effects, depending on the entire setup .... also depending on which other
couplings between the metal and your circuit are existing...
may be connected to ground of your electronics... may be not....
Bye
Markus
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