How to understand the AC equipotential mentioned in course 3.3.4

鬼谷第九

How to understand the AC equipotential mentioned in course 3.3.4 [Copy link]

Discussion based on the lecture on basic knowledge of electronic circuits https://training.eeworld.com.cn/course/3818 How should the AC equipotential mentioned in course 3.3.4 be understood? The video says that from the perspective of DC power supply, from Va=Vb+Vcc, it can be deduced that Va=Va=Vcc-Vb, right? Ask for answers

maychang

From the mathematical formula in the picture, VCC is a constant. A constant means it does not change, so the increment of a constant is zero.

鬼谷第九

But I can't understand the equation Va=Vb+Vcc. And why are the AC potentials at points AB equal? Is it because the changes in AC potentials at points AB are equal?

鬼谷第九

maychang posted on 2017-3-5 09:32 From the mathematical formula in the picture, VCC is a constant. A constant means it does not change, so the increment of a constant is zero.

But I can't understand the equation Va=Vb+Vcc either. And why are the AC potentials at points AB equal? Is it because the changes in the AC potentials at points AB are equal?

maychang

Guigujiujiu posted on 2017-3-5 09:58 But the equation Va=Vb+Vcc is also incomprehensible. And why are the AC potentials at points AB equal? Because the AC potential changes at points AB are equal?

"The equation Va=Vb+Vcc is also incomprehensible." How can this be incomprehensible? We don't know what Vb is, or we can't determine it. But Vb plus Vcc can definitely be Va. This equation simply means that Va is higher than Vb by Vcc.

maychang

Guigujiujiu published on 2017-3-5 09:58 But I can’t understand the equation Va=Vb+Vcc. And why are the AC potentials at AB equal? Because the changes in the AC potentials at two points AB are equal?

“And why are the AC potentials at AB equal? Because the changes in the AC potentials at two points AB are equal?” That’s right. But the second half of the sentence should say “because the changes in the potentials at two points AB are equal”, removing the word “AC”. Because “AC potential” is “potential change”.

鬼谷第九

maychang posted on 2017-3-5 10:20 "Why are the AC potentials at points AB equal? Because the changes in the AC potentials at points AB are equal?" That's right. But the second half of the sentence should say "Because the changes in the potentials at points AB are equal...

Thank you very much