Does the amplitude of sine wave mean peak or peak?

Refers to the peak.

The sine curve y=Asin(ωx+φ)+k is defined as the image of the function y=Asin(ωx+φ)+k in the rectangular coordinate system, where sin is the sine symbol, x is the value on the X axis of the rectangular coordinate system, y is the corresponding y value of the function in the same rectangular coordinate system, and k, ω and φ are constants (k, ω, φ∈R,

Where a- amplitude is 1/2 stroke when the object makes linear reciprocating motion with sinusoidal trajectory.

The peak value is the difference between the highest or lowest value of the signal and the average value in a period of time. The peak value is the maximum value based on the 0 scale, with positive and negative values. So the amplitude of sine wave refers to the peak value.

Extended data:

Effective value of sine wave

Take the angle as time to simplify the calculation.

Let 2π be a period t and a short angle d ~ be a short time d T.

The effective value in the period t is the equivalent voltage with the same heating value in the period t:

The heating value in a period t (assuming the resistance r = 1): ∫ u 2× dt, which is equivalent to ∫u 2×d \

When u = sin \angle:u = sin

Then ∫ u 2× d ∫ = sin 2× d.

Integral in the range of 0 ~ 2π:

So ∫ sin2 \ d \ = (2π/2-1/4× sin4π)-(0/2-1/4× sin0) = π.

The equivalent voltage Uo = =Uo^2×2π generates heat equal to ∫ sin2 d = π.

Therefore: uo 2× 2π = π.