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Because peak to peak measurements are only accurate if the wave is nearly perfectly sinusoidal and without excessive sideband spurs. An average measurment wheather it be done by a gizzmo that did the math for us or an o-scope where we have to divide what we see by 2.828 for the RMS value. A digital voltmeter simply averages all of the voltage changes into "a number" that agrees with what the predicted mathematical value should be. these devices always have frequency limitations. You should slways check the specs of your measuring device before you start to make sure it is capable of making an accurate enough measurement at the freqyency you have in mind.
AnswerAll a.c. voltages and currents are expressed and measured in rms values, unless otherwise stated. So it follows that any calculations would be done using these values.
What else can I help you with?
What is meant by cut in voltage?
Cut-in voltage is the value of voltage at which appreciable current begins to flow when a pn junction is forward biased.
Why current lead voltage in coil?
because a coil is an inductor,for current leads voltage in an inductorAnswerIt doesn't! Current lags voltage in a coil. In a purely-inductive circuit, the current lags the supply voltage by 90 degrees. The reason for this is 'self inductance'. Whenever a current changes, a voltage is induced into the coil which opposes that change in current. The maximum self-induced voltage occurs when the rate of change in current is greatest. The greatest positive rate of change of a.c. current occurs when that current is passing through the zero axis of its waveform, so the greatest (negative) induced voltage occurs at thatsame point, which is one-quarter of the wavelength, or 90 degrees. In accordance with Kirchhoff's Voltage Law, the supply voltage must be in antiphase with the induced voltage. So when the peak induced voltage is negative, the peak applied voltage must be positive. Or, to put it another way, the peak value of the applied voltage must occur 90 degrees before the peak value of the current -so the current lags the applied voltage by 90 degrees.
Is DC voltage and average voltage same?
no, dc volatage is a type of current direct current, ac is alternating current, average voltage could be any type of voltage ac or dc that maintains a constant rangeAnswerNo. A DC voltage is exactly equivalent to an AC rms-voltage. So, for example, 100 V (DC) is exactly equivalent to 100 V (AC rms). The average value of an AC waveform is zero.
What effect a capacitor has on a supply current on an inductive load?
it will improve the power factor... The angle between voltage and current will decrease depends on capacitor value.
What size circuit breaker should be used if you use 5 horsepower of air-conditioning?
To answer this question a voltage value must be given. Circuit breakers protect the conductors that feed the load. The lower the voltage value, the higher the current value, hence a larger the wire size is needed and therefore larger the breaker size for the circuit. In reverse the higher the voltage value, the lower the current value, hence a smaller the wire size can be used therefore smaller the breaker size for the circuit.
What is the relationship between the current and voltage in a pure inductive circuit?
In a pure inductive circuit, the relationship between current and voltage is such that the current lags behind the voltage by a phase angle of 90 degrees. This means that the current and voltage are out of phase with each other, with the current reaching its peak value after the voltage has reached its peak value.
What is rms value in ac system?
The r.m.s. value of an alternating current or voltage is the value of direct current or voltage which produces the same heating effect.
How does the maximum value of the current depend on the frequency of the AC voltage source?
The maximum value of the current in an AC circuit depends on the frequency of the voltage source. As the frequency increases, the maximum current value also increases.
Maximum value of voltage or current?
Amplitude
What is the instant current value in zero voltage?
maximum current will flow in that line
What is the relationship between peak rms and average values of an ac voltage?
Peak voltage of an AC voltage is the value at its highest or lowest point.RMS (Root Mean Square) voltage of an AC voltage is a mathematical derivation involving the square root of the average value of the squares of samples of the voltage as the sample interval approaches zero.Average voltage is simply that - the average or mean voltage.For a true sine wave, RMS and average are equivalent, but they are not equivalent when the wave is distorted, or has some other shape such as triangular.RMS is the best way to measure an AC voltage, as it gives you a true reading of the amount of power that the voltage can deliver.One issue with non-RMS AC meters is that they typically measure the rectified, filtered peak value and then compensate by dividing by 1.4. This is not correct unless the voltage is a sine wave.AnswerThe peak value of an a.c. voltage or current is the amplitude of that voltage or current waveform -i.e. the maximum value of voltage or current in either the positive or the negative sense.The root-mean-square (rms) value of an a.c. voltage or current. For a sinusoidal waveform, the rms value is 0.707 times the peak value (amplitude). A.C. voltages or currents are always quoted in rms values unless otherwise specified.The average value of an a.c. voltage or current is zero over one complete cycle so, when used, it applies only over one half cycle. Therefore, the average value for one-half cycle of a sine wave is 0.637 times the peak value. Average values are of little relevance to a.c. calculations.
What are the functions of current transformers and the difference between current transformers and voltage transformers?
To sense the current flow across the current transformers and to monitor the current ratings. In current transformers no voltage variations occurs. but in voltage transformers it is mainly used to increase or decrease the voltage value.
If the resistance increases what will happen to voltage and current?
If you have a simple circuit. For eg: One voltage source and one resistor, then the voltage of the circuit will always remain the same, the current however will decrease following Ohms' Law V=I*R. If we have a current source instead of a voltage source, we are forcing the current to be a certain value so if we increase the resistor value the current will remain the same but the voltage will increase.
What is the difference between a transformer and a rectifer?
A transformer is used to change the value of a voltage applied to the transformer's primary winding to a different voltage value taken from the transformers secondary winding. A rectifier is used to change an alternating current value to a direct current value.
Does kva equal voltage x current x 1.73 for a 3 phase generator?
Yes, but only for balanced loads (current in all three phases the same value). The voltage value used is the phase to phase voltage.
What is RMS Peak value and average value?
RMS is used to determine the average power in an alternating current. Since the voltage in an A/C system oscillates between + and -, the actual average is zero. The RMS or "nominal" voltage is defined as the square root of the average value of the square of the current, and is about 70.7% of the peak value.************************************************************The r.m.s. value of an alternating current or voltage is the value of direct current or voltage which produces the same heating effect.Fo a sine wave, the r.m.s. value is 0.707 x the peak value.The average value is different; for a sine wave it is 0.636 x the peak value.
What is meant by cut in voltage?
Cut-in voltage is the value of voltage at which appreciable current begins to flow when a pn junction is forward biased.
