RKH said:
It's not what you believe, but what you know. And you know didley squat. Please don't post false answers that only create confusion. Don't be offended but please understand that less experienced member really don't need more confusion.
Question was addressed to Andrew so let him answer. Answers to both Andrew's and Albert's questions can be found in MOSFETs' datasheets.
juma said:
Was that really necessary? He was pretty close if not right. We're all learning here.
Tj is the junction temperature
Ta is the ambient temperature
Thermal resistance is denoted as follows:
R(thetaJC) - junction to case resistance
R(thetaCS) - case to sink resistance
R(thetaJA) - junction to ambient resistance
R(thetaSA) - sink to ambient resistance
The temperature rise of the junction relative to the surrounding ambient temp is given by:
Tj - Ta = R(thetaJA)*Pd
or
Tj - Ta = [R(thetaJC)+R(thetaJA)+R(thetaSA)]*Pd
Pd is the steady state power the transistor is dissipating.
Anyway there are more equations used to calculate heat sink size using the different thermal resistances. I just grabbed this out of an old textbook, don't really remember all the details.
Johnloudb said:
Yeah, the driver that missed the curve and ended on the bottom of the river was pretty close too.
I didn't want to hurt anyone's tender feelings, but to prevent further misleading and false answers which are in contradiction with idea of learning (no one wants to be taught wrongly).
Sorry if I offended anyone.
I have posted some incorrect answers in this forum in an honest and heartfelt attempt to help others and to give back to the forum what little I can.
Thanks RKH for making the same attempt. Your post couldnt have killed anybody.
When I notice that others are wrong and I am sure of it I ask in the forum that someone correct them or, if I know the answer myself I simply interject that answer.
I find Juma's post offensive and mean spirited. His "sorry if I stepped on your pretty little bleeding hearts" response is frankly shameful and not in the spirit of these forums at all.
Juma you have contributed a lot to these forums and I cant remember you posting an incorrect statement at this time. But what you said and the way you said it WAS wrong. Not technically, but ethically.
"I didn't want to hurt anyone's tender feelings, but to prevent further misleading and false answers which are in contradiction with idea of learning "
Its good to know there will no longer be misleading and false answers on DIY now that we have you on duty.
"It's not what you believe, but what you know. And you know didley squat."
Except that in the end it really is what you believe and you find that you never knew didley squat.
Uriah
Thanks RKH for making the same attempt. Your post couldnt have killed anybody.
When I notice that others are wrong and I am sure of it I ask in the forum that someone correct them or, if I know the answer myself I simply interject that answer.
I find Juma's post offensive and mean spirited. His "sorry if I stepped on your pretty little bleeding hearts" response is frankly shameful and not in the spirit of these forums at all.
Juma you have contributed a lot to these forums and I cant remember you posting an incorrect statement at this time. But what you said and the way you said it WAS wrong. Not technically, but ethically.
"I didn't want to hurt anyone's tender feelings, but to prevent further misleading and false answers which are in contradiction with idea of learning "
Its good to know there will no longer be misleading and false answers on DIY now that we have you on duty.
"It's not what you believe, but what you know. And you know didley squat."
Except that in the end it really is what you believe and you find that you never knew didley squat.
Uriah
udailey said:
OK, let's look at it from the bright side.
What do I conclude from your lesson in ethics and goodhearted benevolence:
1. It's OK to post untrue claims, without making an effort to check it out first, as long as they are well-meant.
2. Our utmost purpose here is to pet each other's egos.
-------------------------------------------------------
Sorry Uriah, I don't think so.
People mainly do come here to learn and to progress in DIYaudio hobby (it's more than hobby to many DIYers). Many are confused and without appropriate formal education. Do we want to confuse them further (even in a friendly manner) or to help them to stand on their own legs, to learn more and then become able to contribute to whole community ?
Call me evil, but eternal spoon-feeding taught no one anything.
Once more, take my sincere apologies if you feel offended by anything that I wrote.
juma said:
I don't agree Juma.
Testing ones "beliefs" and ideas is one of the most effective ways to learn. Just as we usually learn best from our mistakes. No one ever generated a new idea by blindly following the experts. DIY audio Members have every right to test their ideas and thoughts without being personally attacked. And, there are many members of expertise on this forum who are happy to correct those who make mistakes.