When viewing a sine wave on an oscilloscope, the peak-to-peak voltage is the easiest amplitude dimension to measure. It represents the total height of the wave, from its highest point (peak) to its lowest point (trough). This measurement is straightforward because it involves visually identifying the two extreme points of the wave on the oscilloscope's display.

The RMS (Root Mean Square) value of an AC voltage is a way of expressing the effective power of the voltage. For a pure sine wave, the RMS voltage is approximately 0.707 times the peak voltage. Since the peak-to-peak voltage is twice the peak voltage, a 340 volt peak-to-peak sine wave has a peak voltage of 170 volts (340/2), and thus an RMS voltage of about 120 volts (170  0.707).

The RMS (Root Mean Square) value of an AC voltage is the equivalent DC voltage that would cause the same amount of heat in a resistor. This is a practical way to compare the 'effectiveness' of AC and DC voltages. The RMS value is particularly useful because it allows for a direct comparison of AC and DC in terms of power delivery to a load, like a resistor.

The RMS value of a sinusoidal waveform is about 0.707 times its peak value. For a peak value of 20 volts, the RMS value is 20  0.707, which is approximately 14.14 volts. This RMS value represents the effective voltage of the AC waveform, equivalent to a DC voltage in terms of the power it can deliver to a resistor.

When applying Ohm's law (V = IR) to AC circuits, it's common to use RMS values for current (I) and voltage (V). The RMS value of a sinusoidal AC waveform is 0.707 times its peak value. This factor is used to convert peak values to RMS values, making it possible to apply Ohm's law accurately in AC circuits.

The effective value of a sine wave, also known as the RMS value, is approximately 70.7% of its maximum (peak) value. This percentage reflects the equivalent DC value in terms of the power the AC wave can deliver. It's a crucial concept in AC power systems, as it allows for meaningful comparisons and calculations involving AC and DC.

AC voltmeters are typically calibrated to read RMS (Root Mean Square) voltage. This is because RMS voltage is a practical measure that represents the effective power of an AC voltage, similar to a DC voltage. It's the value that would produce the same amount of heat in a resistor as a DC voltage of the same magnitude, making it a useful and standardized measure in electrical engineering.

An AC voltmeter is calibrated to read the effective value of an AC voltage, which is the RMS value. This effective value is a measure of the actual power or heating effect of the AC voltage, comparable to a DC voltage of the same magnitude. It's a more meaningful measurement than peak or average values for practical electrical applications.

The RMS (Root Mean Square) value of an AC voltage is the equivalent to a DC voltage in terms of the heating effect it produces when applied to a resistor. This means that an AC voltage with an RMS value of, say, 10 volts, will produce the same amount of heat in a resistor as a 10-volt DC supply.

To find the peak-to-peak voltage from the RMS voltage of a sine wave, you first calculate the peak voltage by dividing the RMS voltage by 0.707 (since RMS is approximately 0.707 of the peak voltage). For an RMS voltage of 120 volts, the peak voltage is 120 / 0.707 ≈ 169.7 volts. The peak-to-peak voltage is twice the peak voltage, so it's approximately 339.4 volts (169.7 volts × 2).

The RMS value of a sine wave is about 0.707 times its peak value. For a sine wave with a peak voltage of 17 volts, the RMS voltage is 17  0.707, which is approximately 12 volts. This RMS value represents the effective voltage of the AC waveform, equivalent to a DC voltage in terms of the power it can deliver to a resistor.