How is sinusoidal alternating current produced and what is sinusoidal alternating current?

Sinusoidal alternating current: Voltage and current that change regularly are called alternating current.

Alternating current is the electricity with changing frequency, the formation of alternating current with filial piety is actually caused by the continuous flow of current and reverse flow, simply put, the current from left to right immediately becomes from right to left, the frequency is extremely fast to convert between the two, in fact, there is a very short time in the middle Lu Jingzhu is in a state of power-off, but because the time is too short, the naked eye can not distinguish. Therefore, if you carefully ** the lamp beads of your home, you can find a very subtle flickering situation, which is caused by the alternating current stopping and breaking for a while, and constantly changing the direction of the current flow.

The sine manuscript rolls alternating current.

That is, when the alternating current is transformed, its frequency is a sinusoidal function.

so it's called sinusoidal alternating current.

When the coil rotates in a magnetic field, the wire cutting the magnetic field line will induce an electromotive force, which can be expressed as a sinusoidal curve. If we take three coils, we will bury the clumps at an angle of 120 degrees in space, and the three coils will still rotate at the same speed in the magnetic field, and we will definitely induce three bending sensitive electromotive forces with the same frequency. 1

1.Sinusoidal AC voltage: U=umsin( t+u), U-voltage instantaneous value (V), U-voltage maximum value (V), U-angular frequency (rad s).

2.Sinusoidal AC current: IMSIN ( T + i), U - Voltage instantaneous value (V), Um-Voltage maximum value (V), U - Current initial phase angle (RAD).

An electric current whose magnitude and direction change with a sinusoidal pattern over time is called a sinusoidal alternating current, or alternating current (AC or AC) for short. In our daily life and production, a large amount of electrical energy is sinusoidal alternating current.

Sinusoidal alternating current has the following characteristics:

1 The AC voltage is easy to change.

In the power system, the application of transformers can easily change the voltage, and high-voltage transmission can reduce the losses on the line; Reduce the voltage to meet the voltage level of different electrical equipment.

2 The alternator is simpler than the DC generator.

Sinusoidal alternating current is the voltage and current that change over time according to the law of the sinusoidal function. Since the magnitude and direction of alternating current change over time, that is, the value of voltage (electromotive force) and current is different at each instant, it is important to indicate the positive direction when analyzing and calculating AC circuits.

Sinusoidal alternating current: Voltage and current that change regularly are called alternating current.

The three elements of sinusoidal alternating current are the maximum, angular frequency and initial phase, and knowing the three elements can write its mathematical expression, and its waveform diagram can be drawn, so these three physical quantities are called the three elements of sinusoidal alternating current.

a) Maxima (also known as cluster height peak or amplitude), em, um, im

The maximum value is the maximum instantaneous value. There must be a positive value and a negative value twice in a cycle.

b) angular frequency ( ).

The angle at which the sinusoidal alternating current is located at any moment is usually called the electrical angle, and the electrical angle is 360° for each change of the cycle, also known as 2 radians (rad). The angular frequency is the radians of the sinusoidal alternating current that changes in seconds, and is represented by a symbol in radians seconds, which is represented by the symbol Wisdom rad s. Because the radian of an alternating current is 2 per week, an alternating current with a frequency f changes in an arc of 2 f in one second, and the angular frequency can be expressed as:

2 f c) initial phase and phase difference - 2

The initial phase is the phase of the sinusoidal quantity at the beginning time. On the waveform diagram, the initial phase is defined as the angle between the starting point of the positive half wave and the coordinate origin. When =0, the starting point of the positive half-wave falls exactly on the origin o; When 0, the starting point of the positive half-wave is to the left of the origin o; When 0, the positive half-wave starts to the right of the origin o.

1. The rectangular coil is stationary and generates sinusoidal alternating current in a sinusoidal changing magnetic field.

2. The rectangular coil rotates in a uniform magnetic field to produce sinusoidal alternating current.

3. The coil passes through a sinusoidal magnetic field to generate sinusoidal alternating current.

Fourth, the straight metal rod sweeps through the sinusoidal closed coil in the uniform magnetic field to generate sinusoidal alternating current.

5. The rectangular coil vibrates in a bounded uniform magnetic field to produce sinusoidal alternating current.

6. Sinusoidal alternating current is generated in the transformer secondary coil.

7. Produced in a rolling coil (not closed).

8. The metal rod permeates the ruler in the uniform magnetic field and cuts the magnetic inductance line to produce sinusoidal alternating current in the sub-coil of the transformer.

When t=, the maximum value of this waveform comes for the first time.

<> the maximum value of this sine wave is umax=100v, and the period t=.

f=1/t=1/，ω2π×f=2π×50=100π=314（rad/s）。

The voltage phase is: =.

So: u(t)=umaxsin( t+ )100sin(100 t+ 4)=100sin(314t+45°)(v).

If a cycle is 20ms, then half a cycle is 10ms, that is, the time difference from t to t is 10 2=5ms (quarter cycle), that is:

t-（，t=。

The image in the title is not very accurate, and the vertical axis should be in the middle of (and t.

You can also find t:, depending on the expression

The first occurrence of the maximum, that is, the maximum value of the sinusoidal function is obtained only by the reed, sin (100 t+ 4) = 1, then: 100 t+ 4 = 2,100 t= 4, t=1 400(s) = clear s)=.

The three elements of sinusoidal alternating current.

If the magnitude and direction of the current, voltage, and voltage both change with time according to the sinusoidal law, it is called sinusoidal alternating current.

The three elements of sinusoidal alternating current.

The three elements of sinusoidal alternating current are amplitude, frequency, and initial phase angle. The amplitude of sinusoidal alternating current reflects the range of change of sinusoidal alternating current, and the angular frequency, period, and frequency reflect the speed of change of sinusoidal alternating current. The initial phase reflects the starting state of a sinusoidal alternating current.

1.Amplitude. The current of sinusoidal alternating current is:

im is the maximum value of sinusoidal alternating current, also known as amplitude.

2.Frequency. Several ways to describe the cycle of change:

Period t: The time it takes to change in one week Unit: seconds before laughing, milliseconds.

Frequency f: Number of changes per second Unit: Hertz, kilohertz....Angular frequency: radians that change per second Unit: radians seconds.

3.First phase. The current of sinusoidal alternating current is:

t+) The phase angle or phase of the sine wave.

The phase at t=0 is called the initial phase angle or initial phase.

The starting point or reference point for observing sine waves is given, and it is often used to describe the relationship between multiple sine waves.

Alternating current refers to the current that periodically changes in the direction of the current with the rise of time, and the average current in a period is zero.

The average running value over a period is zero. Unlike direct current, its direction changes over time, and direct current does not change periodically.

Direct current, also known as "constant current", is a constant current of direct current that does not change in magnitude and direction of du, which means that the magnitude (voltage level) and direction (positive and negative electrodes) do not change with time (relative range), such as dry batteries.

Pulsating direct current means that the direction (positive and negative) does not change, and the size of the direct current changes over time.

The voltage and current whose magnitude and direction change with time are called alternating current, also known as alternating current. Sinusoidal alternating current is the voltage and current that change over time according to the law of the sinusoidal function. The magnitude and direction of the alternating current leaked from the AC circuit change over time, that is, the value of the voltage (electromotive force) and current is different at each instant, so it is necessary to indicate its positive direction when analyzing and calculating the AC circuit.