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There are two reasons one cares about polarity in AC circuits: safety and phasing.
In a common household circuit, we are concerned with safety. One side of the AC line, called the "neutral", is at the same voltage as ground. This side of a common outlet is identified by the wider slot and plugs have a wider blade. In the wiring, the neutral is white. On wiring devices, the neutral wire connects to a silver colored screw. On appliance cords, especially flat, two-wire "zip" cord, the neutral side usually has a rib or ribs to identify it. Sometimes this rib is very subtle, like a square corner on the neutral lead where the hot lead is completely round.
The other side of the line is the "line" or "hot" wire. In household wiring, this side is black or red. It corresponds to the narrow slot in an outlet and connects to a brass colored screw.
Circuit breakers and switches are supposed to be wired in the hot lead so if they are turned off, both sides of the connected receptacle or light socket are at neutral potential. If this were not the case, you could get a shock from a light socket which is turned off, if you were also touching a grounded contact of some kind. For further safety, the larger annular threaded contact in a light socket is supposed to be connected to the neutral and the smaller button contact to the line side.
Years ago, this was even more important because household electrical appliances were often made of metal. Plastic wasn't as common. The metal would sometimes be connected to the neutral wire. If the polarity was reversed, the metal case would be "hot". Many old tube-type radios had no transformer in their power supply and the chassis was connected directly to the wide blade of the plug. If the receptacle was wired wrong, the whole radio would be "hot".
The second reason we care, phase, relates to more complex wiring such as three-phase circuits and in electronics. AC voltages are really DC voltages at any particular instant in time and thus have polarity. The polarity of these instantaneous DC voltages is just as important, and for the same reasons, as constant DC voltages.
"Phase" refers to the relative polarity of these instantaneous DC voltages among a related group of AC voltages. If you wire two AC sources in series and they are "in phase" then the voltages add as expected. If one source is reversed, then the voltages subtract. Similarly, paralleling two AC sources which are out of phase, will have the same result as paralleling two DC sources with opposite polarity - a fire.
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Is the LM3914 IC protected against reverse polarity?
i would never naturally assume any circuitry to be "reverse polarity" by default even if they are. since this can fry a lot of IC, and micro controllers. there are several options to adding a reverse polarity protection circuit to your project you can find three easy to implement circuits here: http://provideyourown.com/2012/reverse-polarity-protection-circuits/
What is the difference while applying kcl to dc and ac circuits?
KCL is Common to both AC and DC. Only the waveform or AC and DC will differ
Can you reverse the polarity of AC and DC?
We have the capacity to reverse the polarity of a DC voltage, at least as regards what we apply it to. When we consider a DC motor, like, say, the ones in the little "robot wars" we see on TV, the motors can be run in reverse by reversing the polarity of the applied DC voltage. We normally consider AC as already reversing its polarity. It is, after all, AC, which is alternating current. The current alternates because the voltage alternates. We'll avoid any further discussion of the polarity of AC voltages here and leave it at that.AnswerThe problem, here, is that 'polarity' has several different meanings.Polarity, in the sense of 'electric charge' cannot really be applied to a voltage (potential difference) although it can be to a potential (although the polarity is relative; it depends on the point of reference).Polarity, in the sense of 'direction', can be applied to a voltage. For example, is the voltage acting clockwise or counter clockwise around a circuit?Polarity, in the sense of 'connection', can be applied to a voltage. For example, it's important that the line conductor is connected to the centre terminal of an Edison lamp holder or to one or other of the slots in a receptacle (power socket).
Capacitor inductor circuit which smooth out rectified ac voltage are known as?
filter circuits
How do you energize a furnace relay?
BY applying a voltage to the relay's coil connections. Could be DC or AC at a specific voltage. If it's DC, watch the polarity. If it's AC, polarity doesn't matter. HOWEVER, VOLTAGE DOES MATTER, so don't go applying 120 VAC to a relay when it needs only 16 VAC, and DON"T APPLY AC to a DC relay. Could burn up quite nicely if you're not careful.
Do integrated circuits have polarity?
Yes integrated circuits have polarity.
A reversed polarity is when the hot and neutral are wired backwards?
Yes in AC circuits the terminology reversed polarity means the hot and neutral are reversed to what they should be. In DC circuits reversed polarity means that the positive and negative terminals are reversed to what they should be.
Do ac capacitor have polarity?
no
Does a series circuit always use one battery?
Any circuit may use as many power sources as you wish. For DC circuits you must maintain the same polarity. For AC circuits you must synchronize frequency and match voltages.
Why ac current attract?
As we touch an ac supply in which due to body resistance , we create a phase difference between the ac supply and us . As ac reverses polarity , so do we , but our polarity change is opposite to that of the polarity change of ac supply , hence our body gets attracted to the ac supply .
What does negative polarity mean with electricity?
Polarity is the direction of flow of electrons throughout a circuit. There are two types of polarity: positive and negative. Postive polarity is of older circuits which means electrons flow from positive to negative. Negative polarity is of more modern circuits and that is the flow of electrons from negative to positive such as on car batteries
Which current is having high polarity?
ac(Alternating Current ) has the high polarity.
Why is the lead polarity not significant when measuring AC voltage?
Because the polarity is changing at a 60 Hz rate. Hence the world alternating in AC.
What is the difference between AC MCB and DC MCB?
In AC circuits (regular household circuits), the voltage source changes the polarity of its output regularly. In India, this happens 100 times per second. By contrast, in DC circuits, the current flow is unidirectional due to the fixed polarity of the voltage source. This leads to undisrupted, longer and sustainable arcs in DC circuits (the reason why arc welding machines use DC current and not AC current). While breaking a DC circuit, it is easy to form such arcs, and if they are not extinguished in time they lead to device overheating and ultimately to fire. AC circuit breakers are not equipped well enough to deal with such arcs, whereas DC circuit breakers have special arc chutes to capture arcs and extinguish them safely, hence they are highly recommended.
What are the main difference while applying kirchoffs laws to dc circuits and ac circuits using meter readings?
For DC circuits, an alebraic sum is required. For AC circuits, a phasor sum is required.
Do ac capacitor have positive and negative polarity?
both
How do you reverse polarity on ac motor?
Reversing polarity is not possible with an ac motor. Some do have wiring that will allow you to change rotation. The type and model of the motor can tell you if it is reversible.
