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There is no direct comparison but this is one way to look at it...

120v ac, if measured correctly, is the effective voltage of the circuit and is basically the same as 120v dc for items that can run on either. Not many things besides purely resistive circuits, such as incandescent lights, can run on either. Effective voltage is not the same as average voltage, another way of measuring volts.

Alternative Answer

Unless otherwise stated, an a.c. current is alwaysexpressed as a root-mean-square (r.m.s.) value. This is the value of a.c. current that will do exactly the same amount of work as a d.c. current of the same value. In other words, 5 A (for example) a.c. is exactlyequivalent to 5 A d.c. Since voltage is proportional to current, we can say the same thing about a.c. voltages. So, 120 V a.c. is exactly equivalent to 120 V d.c.

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Rms value defination?

Because alternating current (AC) voltage varies over time, to the positive and negative, an actual AC voltage measurement will not be the same as a DC voltage measurement. For example: 5 volts DC is 5 volts constantly, viewed over time. The average voltage is 5 volts. 5 volts AC (from zero to peak) is not actually 5 volts constantly, but varies between 5 volts and 0 volts over time. The average voltage will not be 5 volts. Using RMS AC values is designed to make AC and DC measurements equivalent, for example 5 volts DC and 5 volts RMS AC are almost identical.


Is there a 120 AC dimmer switch wiring diagram for 24 volt DC motor?

The output of a 120 volt dimmer switch will be an AC voltage so should not be used on a DC motor.


Does DC adapter mean the device converts DC to ac or ac to DC?

An AC adapter adapts the device that one wants to power up to the AC line. That means it converts the AC line voltage to something that can be used by the device in question. An AC adapter converts AC to DC. (In contrast, a device that runs off DC and makes AC out of it is called an inverter. An example of an inverter is the device that plugs into a vehicle's cigarette lighter and has an outlet on the other end that will permit someone to plug something like a kitchen blender into it. Great for tailgating! Don't run your vehicle's battery down....) There are times when an AC adapter is the little plug-in-the-wall thingie that converts the AC line voltage to some lesser value of AC. There are a few devices out there (usually older ones) that used their AC adapters to step down the wall voltage (115 volts AC) to 24 volts AC, 18 volts AC, 9 volts AC, or anything like that. Some new sprinkler control timers use an adapter that is an AC -to-AC step down converter. By looking at the information on the adapter, the user can see what the primary voltage is (and it's almost invariably 115 volts AC or 120 volts AC - same, same for this application) and what the secondary voltage is. As stated, the secondary is almost always DC, and if it is, the polarity is almost always indicated as well. That's so a user can tell if that little round connector has positive on the inside and negative on the outside or the other way round. (It makes a lot of difference to the device on which it is used, as one might guess.)


What is the ac equivalent of 98v DC?

120 volt single phase rectifies to about 96 volt DC


How do you convert hertz into volts?

'Hertz' is the modern name for 'cycles per second' and represents how many times an alternating current (AC) changes from + to - per second and has nothing to do with voltage that can be either AC or DC. Tus if you have an alternator and can rotate the shaft 60 times per second with a voltage of 120 volts you will produce the same AC voltage that you find in your wall outlet (Alternators produce AC while generators produce DC electricity.

Related Questions

Can you charge battery from ac?

No, it must be charged with a battery charger plugged into 120 volts AC which converts it to 12 volts DC.


Is 12 volts dc as powerful as 120 volts ac?

You get power by multiplying the amperes and the voltage. 12V, 10A dc would give the same power as 120V, 1A ac.


How do you calculate the ac amps when you have the DC volts DC amps and the ac volts?

the answer is dc volts are rectified from ac volts and the amperage will be the same unless you account for the slight drop from the rectifier. dc volts from a battery have no relationship to ac volts. you can derive ac volts from a dc source using an inverter.


Why AC is dangerous as compare to DC for same amount of voltage?

The danger is in the voltage, not if it is ac or dc. For instance, 12v dc or 12v ac makes no difference in body contact. Neither will shock you. Usually 24 volts will not shock either. When you get to 48 volts or greater, then you have a chance of shock. 100 volts Ac or Dc shocks basically the same. 120 volts AC is actually 144 volts peak to peak, so 120 volts AC is slightly worse than 120 volts DC. Amperage is actually what kills. A "Taser" voltage can be as high as 50,000 V but the amps are so slow that it doesn't do permanent damage. Commonly people are shocked accidentally by a spark plug wire on a car or a lawnmower with no lasting or ill effects. This voltage can range from 15,000 volts to more than 50,000. These systems have very low amperage.


How can you 120 volts AC to 5 volts DC?

By a DC power supply that runs at 230 volts AC. Basically, you need a full wave rectifier (4 diodes) to convert AC into all positive voltage. Then you need capacitors to smooth out the ripple and then various resistors to reduce the voltage.


Can dc bulbs work on ac?

Yes- ac or dc makes no difference to a regular light bulb. However, it must be the correct voltage. DC bulbs used on a car are 12 volt, and household AC current is 120-240 volts.


Can DC bulbs work on AC current?

Yes- ac or dc makes no difference to a regular light bulb. However, it must be the correct voltage. DC bulbs used on a car are 12 volt, and household AC current is 120-240 volts.


If a battery has 100 amp hours at 12 volts dc how many amp hours will it have with a 120 volt ac inverter connected?

The amp hours capacity of a battery remains the same whether it is connected to a 12-volt DC load or a 120-volt AC inverter. So, the battery would still have 100 amp hours regardless of the inverter voltage.


What is an ac voltmeter?

A: It is a regular DC voltmeter but the AC is rectified and the DC component is measured and displayed as AC VOLTS.


The working voltage of a capacaitor is rated in ac or dc volts?

DC


Is a car cigarette lighter socket ac or dc?

12 volts DC


What is effective voltage?

It is the 'as if' voltage in an AC circuit. Referred to as Vrms 120 volts in your house is Vrms, the effective voltage, 'as if' it were DC 120V, can do the same work. But 120VACrms is a sine wave with a peak voltage much higher than 120 volts.