Problems of RCL series parallel circuit "Given the resistance current IR = 8A (R is the bottom pin), inductance current IL = 3A, capacitance current IC = 9 of RCL parallel circuit, what is the terminal current I?"

1. In a parallel circuit, the current on the inductor and the current on the capacitor are opposite and should be subtracted
│Ic│-│IL│=9-3=6A
2. The direction of 6A current above is the same as that of the current on the capacitor, but it is 90 degree phase difference from that of the current on the resistor. When it is added in parallel with the current on the resistor, it is the sum of the squares of the two and then the square
I total = √ (8 * 8 + 6 * 6) = 10A
This is the current value of the main road
finish

There is a section of conductor in the circuit. When a voltage of 20mV is applied to it, the current passing through it is 5mA Ω, if 30 mV voltage is applied to it, its resistance is Ω; if no voltage is applied to it, its resistance is__ Ω．

(1) ∵ u = 20mV = 0.02v, I = 5mA = 0.005a, ∵ the resistance of the conductor is r = UI = 0.02v0.005a = 4 Ω; (2) ∵ the resistance of the conductor is independent of the voltage at both ends and the current passing through, ∵ when the voltage at both ends of the conductor changes to 30mV, the resistance of the conductor remains unchanged, which is still 4 Ω; when no voltage is applied to it, the resistance of the conductor remains unchanged, which is 4 Ω

When measuring the impedance angles of R, l and C elements, why should a small resistor be connected in series with them? Can a small inductor or a large capacitor be used instead? Why?

Because the resistance is a pure resistive element (the impedance is a real number), but in reality, neither inductance nor capacitance can be pure inductive or capacitive (the impedance is a pure imaginary number)
In this way, the voltage and current on the resistor are almost strictly in the same phase in a wide frequency range, so the voltage on the resistor can be used to represent the current passing through the component to be tested, and the impedance angle can be obtained by comparing with the voltage of the component to be tested

Given x2-3x-5 = 0, find the value of x3-14x + 15

x2-3x-5=0
x²-3x=5
x3-14x+15
=x(x²-3x)+3x²-14x+15
=3x²-9x+15
=3(x²-3x)+15
=3×5+15
=30

In parallel hexahedron ABCD-A ` B ` c ` d ', the bottom surface of ABCD is rhombic, and

Connect BD, AC, intersect at g, know that AC is perpendicular to BD. (1) connect, BC ', DC'. Easy to prove that triangle CBC 'is equal to CDC', deduce: BC '= DC'. Know: Triangle BDC 'is isosceles triangle, connect c'g. know as the middle line, deduce: c'g is perpendicular to BD. (2) from (1) (2) know that BD is perpendicular to plane acc'a'

X squared-7x-12 = 0

The formula x = [- B ± (b ^ 2-4ac) ^ (1 / 2)] / 2a, where a = 1, B = - 7, C = - 12

Given the set M = {X / x ^ 2 + 2x-a = 0} 1. If the empty set contains M, find the value range of real number a
2. If n = {X / x ^ 2 + x = 0} and M is contained in N, find the value range of real number a

1. According to the meaning of △ = 2 ^ 2-4 (- a) > = 0, we get that a > = - 12, the solution equation x ^ 2 + x = 0, n = {X / x ^ 2 + x = 0} = {0, - 1} is substituted into the equation x ^ 2 + 2x-a = 0, a = 0, the equation x ^ 2 + 2x-0 = 0 has solution, X1 = 0, X2 = - 2, M = {0, - 2}, m does not contain in NX = - 1, a = - 1, the equation x ^ 2 + 2x - (- 1) = 0 has solution, X1 = x2 = - 1, M = {- 1}, m contains in

1111111 play an idiom? 3.5 play an idiom? 2468 play an idiom? 24 hours play an idiom? 1 / 100 play an idiom?
1111111 play an idiom? 3.5 play an idiom? 2468 play an idiom? 24 hours play an idiom? 1 / 100 play an idiom?

Unique
indecent
it happens that there is a similar case
a short duration of time
only one in a hundred is chosen

There are several ways to put two triangles with 5cm, 6cm and 7cm sides into a parallelogram. What are their perimeter?

Three, 5 = 22
5 5 7 7 =24
6 6 7 7=26

Solution equation: 40% x + (40% X-12) + 28 = x

40%X+（40%X—12）+28=X
0.4x+0.4x-12+28=x
0.8x+16=x
0.2x=16
x=80

Problems of RCL series parallel circuit "Given the resistance current IR = 8A (R is the bottom pin), inductance current IL = 3A, capacitance current IC = 9 of RCL parallel circuit, what is the terminal current I?"