When analyzing the amplifying circuit, draw the AC path diagram. Why can the DC power supply be regarded as a short circuit?

When analyzing the amplifying circuit, draw the AC path diagram. Why can the DC power supply be regarded as a short circuit?

The internal resistance of DC power supply is very small, which can be ignored in the analysis of amplifying circuit. It is regarded as a path, so drawing AC path diagram is regarded as a short circuit

What is the phenomenon of short circuit between AC power supply and DC power supply

Voltage / resistance = current. In case of short circuit, the resistance of the line is very small and tends to 0. It can be seen from the formula that the current will be very large. If the current is too high, the wire will be heated and ignited. If the power is supplied by a transformer, the large current will damage the transformer. If the power is supplied by an electronic equipment, the equipment will be damaged

When drawing the small signal equivalent circuit of amplifier circuit, the DC power supply in the circuit is often short circuited. How to understand this?
That is to say, the positive end of DC power supply VCC is regarded as DC positive potential and AC ground potential

Compared with AC, DC power supply is similar to short circuit

Given that an ellipse passes through the moving point m (1,0), taking the straight line x + 2 = 0 as the guide line and the eccentricity as 1 / 2, the trajectory equation of the left vertex of the ellipse is obtained

Because the ellipse passes through M (1,0) and takes x = - 2 as the guide line, so the ellipse is on the right side of the straight line x = - 2. Let P (x, y) be the left vertex and Q (a, y) be the left focus. From the definition of the ellipse, we can get | MQ | / 3 = 1 / 2, and | PQ | / (x + 2) = 1 / 2, (x > - 2). The coordinates are (A-1) ^ 2 + y ^ 2 = 9 / 4, A-X = 1 / 2 *

The bottom and height of a parallelogram are 1.6m, and its area is______ M2, and the area of the triangle with the same base and height is m2______ m2．

1.6 × 1.6, = 2.56 (square meters); 1.6 × 1.6 △ 2, = 1.28 (square meters). Answer: the area of the parallelogram is 2.56 square meters; the area of the triangle with the same base and height is 1.28 square meters

M (- 1,2), n (5,2), | PM | - | PN | = 6, then the trajectory equation of P is

The distance of Mn is 6. According to the principle of the shortest straight line distance between two points, it is concluded that the distance of Mn is 6
6=|PM|-|PN|=5

The width of a rectangle is 3A + 2B, and its length is 2a-b more than its width

The radius of the circle O is 5, P is a point in the circle, Po = 4. ① through the point P, make the string AB, make PA = Pb, ② find the length of the string ab

The length of string AB is 6

As shown in the figure, in △ MNP, h is the intersection of high MQ and NE, and QN = QM. What is the relationship between PM and HN? Try to explain the reason

Proof: PM = HN. Reason: ∵ in △ MNP, h is the intersection of high MQ and NE, ∵ meh = ∵ nqh = 90 °, mqp = ∵ nqh = 90 °∵ MHE = ∵ nhq (equal to vertex angle), ∵ EMH = ∵ QNH (equal to remainder angle of equal angle), in △ MPQ and △ nhq, ∵ mqp = ∵ mqhqm = QN ∵ PMQ =