How to determine capacitance and resistance in RC phase shift circuit In the circuit, RC is used to shift the phase, such as 30 degrees or 60 degrees. At this time, how to determine the value of R and C, it is best to give a certain formula, even if it is related to the load, thank you! It's better to give an example. Sometimes the oral description is a little vague; In addition, according to the vector diagram of resistance, capacitance and inductance, when there are only capacitance and resistance, the phase will be zero Only lag, how can there be lead? Please explain!

The impedance of R is a real number and the impedance of C is 1 / (JWC). After calculating the total impedance of the circuit, the phase change can be obtained by using the ratio of the imaginary part and the real part of the impedance to calculate the arctangent
That should be clear
After calculating the phase, - 180 ° is no phase shift, from - 90 ° to - 180 ° is lead, and from - 180 ° to - 270 ° is lag
When the capacitor is connected in series with the circuit parameters, the effect of voltage division increases, and the effective signal added to both ends of the amplifier element decreases, resulting in leading. Similarly, when the capacitor is connected in parallel, it can be calculated that it is lagging

Why is the total current minimum and the total impedance maximum in parallel resonance? I'm confused about the relationship in parallel resonance. Which master can give me some advice

Natural laws exist objectively. Scientific theory is people's interpretation of natural laws. Many physical phenomena have different interpretations at different levels. You should not pay too much attention to the concept of "knowing why", just remember their characteristics. Parallel resonance is also called current resonance. During resonance, the reactive current components of two branches cancel each other

How to find the expression of current in LC parallel resonant circuit
Such as the title
Please write it down
ω0C=ω0L/[r^2+(ω0L)^2]
What do you mean, please?

When one branch is R L and the other is C, the currents of the two branches are IL = u / (R + J ω L) and ic = Ju ω C, respectively
The total current outside the loop I = IL + ic = u {R / [R ^ 2 + (ω L) ^ 2] + J {ω C - ω L / [R ^ 2 + (ω L) ^ 2]}
At resonance, ω 0C = ω 0l / [R ^ 2 + (ω 0l) ^ 2], that is, ω 0 = √ (1 / lc-r ^ 2 / L ^ 2)
If R ＜ √ (L / C), then ω 0 = √ (1 / LC) = 1 / √ (LC) or resonant frequency f0 = 1 / [2 π √ (LC)], then I = ur / [R ^ 2 + (ω L) ^ 2], I and u are in phase
The above is the answer of 5-28 02:18
“ω0C=ω0L/[r^2+(ω0L)^2] ”
ω 0: angular frequency at resonance, 2 π F0. F0: resonant frequency
Capacitance reactance at resonance: 1 / ω 0C
Inductive reactance at resonance: ω 0l
Square of impedance value of RL series connection at resonance: [R ^ 2 + (ω 0l) ^ 2]
J {Omega C - Omega L / [R ^ 2 + (omega L) ^ 2]}: if the value of Omega C is equal to that of Omega L / [R ^ 2 + (omega L) ^ 2], then the part after J will be zero. Therefore, the total current I and voltage U outside the circuit will be in phase, and there is no phase difference, which means resonance
The real part of the complex number is equivalent to the x-axis of the X-Y coordinate system, and the imaginary part is equivalent to the y-axis. The imaginary part is 90 degrees ahead of the real part. The real number R with positive pure resistance and the imaginary number J ω l with positive pure inductance, The imaginary number with negative pure capacitance is 1 / J ω C = - J / ω C
If you have a certain foundation, it will be easy to understand

The earth attracts dust, so does dust?
The earth attracts apples, so do apples?
The attraction of the earth to a person is 700n. Does a person also attract the earth with 700n gravity?

All right
Because force = reaction

3.75 - [(- 3 / 8) + (- 1 / 2) - (- 5 / 6) + 4 and 2 / 3] - 0.125 steps

3.75 - [(- 3 / 8) + (- 1 / 2) - (- 5 / 6) + 4 and 2 / 3] - 0.125
=3.625-[-(3/8+1/2)+5/6+14/3]
=3.625-(11/2-7/8)
=3.625-37/8
=3.625-4.625
=-1

A resistance wire is connected in the circuit. When the voltage at both ends of the resistance wire increases from 15 V to 20 V, the current increases by 5 A. how much is the electric power increased?

When the voltage at both ends is 15 V, the current through the resistance wire is I = u / r = 15 V / R. when the voltage at both ends is 20 V, the current through the resistance wire is I '= u' / r = 20 V / ri '- I = 20 V / R - 15 V / r = (20 V - 15 V) / r = 5 A. the resistance wire is r = 1 ohm

Practical problems in the first semester of junior high school
A person can walk 6 km / h and ride a bicycle 18 km / h. from a to B, half the distance is walking and half the distance is riding a bicycle. After arriving at B, he returns to a, half the time is walking and half the time is riding. As a result, the time of returning is 1 / 3 hour less than that of going. What's the distance between a and B?

12km
(x/12+x/36-1/3)/2*(6+18)=x
x=12 km

Calculate the conversion standard of meter and kilogram of natural gas spiral pipe L415 with diameter of 508 * 8.7. Please list the calculation formula and results

(508-8.7) * 8.7 * 0.0246615 is the weight per meter (kg)

What's the inspiration for you? Please combine your study and life, say it and write it down

Drop of water wears away stone. It means that as long as we have perseverance and keep working hard, we will succeed. In our life and study, we also need this kind of persevering spirit. Hard work is the foundation of success. Only by keeping working hard can we succeed in our career

How to calculate the fuel consumption of marine diesel engine

The fuel consumption rate is generally 170g / kWh