# Ac voltage

High voltage transmission lines deliver power from electric generation plants over long distances using alternating current. These lines are located in eastern Utah. High voltages have disadvantages, such as the increased insulation required, and generally increased difficulty in their safe handling. In a power plantenergy is generated at a convenient voltage for the design of a generatorand then stepped up to a high voltage for transmission. In one of the earlier examples, the power output of an amplifier was expressed as peak power. The voltage used to calculate the power output into the resistive load was peak voltage. The next section will explain the different ways to measure voltage.

There are 3 ways to quantify the magnitude of a sine wave. Peak voltage tells you how far the voltage swings, either positive or negative, from the point of reference. Peak voltage is only a moderately useful way of measuring voltage when trying to express the amount of work that will be done when driving a specified load.

Some manufacturers use peak voltage to get the power output ratings of their amplifiers. I will explain this in more detail a little later. It is rarely used. It is probably more useful in the case of a non-symmetrical wave form.

Otherwise you would probably express it's value as peak voltage. It is Ac voltage the most useful. Because AC Ac voltage is constantly changing and is at or near the highest and lowest points in the cycle for only a tiny fraction of the cycle, the peak voltage is not a good way to determine how much work can be done by an AC power source e.

DC voltage is constant. Its voltage level can be plugged directly into the formulas for power on the Ohm's law page and you will get an accurate image of its ability to do work. RMS voltage will give you the same ability to predict how much work will be done by an AC voltage. If you read voltage with a voltmeter you are generally given the RMS voltage of the wave form.

Some meters display an 'average' voltage which is very close to RMS. When reading voltage with a voltmeter, the display indicates the RMS or average voltage not the peak or peak-peak voltage. For more complex signals, you need a meter that will calculate the RMS value from a set of samples taken at regular intervals.

More on RMS Voltage: In the following diagram, the 'filled' area is where the sine wave will do some work motivating speakers, etc. The amount of work that it will do at any given point in time is determined by the magnitude above and below the reference of the voltage with reference to the red line.

If you look at the the blue area of the diagrams, this is equal to this.

## Medium voltage AC - ABB Drives

The 'negative' voltages were simply converted to positive voltages for clarity. The green area is the equivalent DC voltage.

As you can see in the diagram below, for the same period of time, the AC voltage is sometimes lower and sometimes higher than the DC voltage.

The amount of work that can be done by the voltages in this diagram is the same. Of course when I say they are equal in the amount of work they can do, I am talking about something like heating a heating element or driving an electric motor and not audio reproduction audio is an AC waveform.

If you have a 'true RMS' voltmeter, the meter measures the instantaneous voltage at regular time intervals. On the following graph, the little vertical lines along the sine wave represent the points in time where the voltage is measured.

The microprocessor in the voltmeter then 'squares' all of the voltages at each point and adds the squared values together.

It then calculates the average mean from the squared values. The following is a sample of the data that's used to calculate the true RMS voltage of a 1 peak volt sine wave. As you can see the values come out to the same value as when you multiply the voltage 1 volt in this case by 0.

A word of caution, many manufacturers of car audio can exaggerate their power ratings by using peak power derived by using peak voltages. Peak power is twice as much as RMS power and is not indicative of the actual amount of work that the amp will do driving your speakers.

Many people wrongly believe that the RMS power rating is the same as a continuous power rating. First, power is a 'snapshot' of the amount of work being done at any point in time.Alternating Current (AC) Alternating current describes the flow of charge that changes direction periodically.

As a result, the voltage level also reverses along with the current. AC is used to deliver power to houses, office buildings, etc. Generating AC. AC can be produced using a .

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Simran AC Step Up/Down Voltage Converter Transformer V/V - Watts. AC voltage measurement using pic microcontroller and ashio-midori.com have came across many online tutorials on various websites about voltage measurement using different microcontrollers.

But all these tutorials are about measurement of low DC ashio-midori.com this project, you will learn how to measure high AC voltage using PIC16fA micrcontroller. Get information on medium voltage multi-level IGBT drives by Hitachi America, Ltd.