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If a negative current enters a negative voltage will it be negative or positive?
Wiki User
∙ 11y ago
A current is never concidered negative. The current will always flow from a higher voltage to a lower.
For example:
12 -> 0V as 12V is a higher potential than 0V. The current is measured in Ampere.
0V -> -12V as 0V is a higher potential than -12V. The current is measured in Ampere. Not negative Ampere despite the fact that it floats from the 0V potential
AnswerThe term 'negative', in the sense of 'polarity', doesn't apply to either current or voltage (potential difference), although it does apply to potential -so, the previous answer should read that current 'flows from a higher potential to a lower potential', not 'from a higher voltage to a lower voltage'.
However, we do use the terms 'negative' and 'positive' in the sense of 'sense' or 'direction'. So, when we talk about a 'negative voltage', what we mean is a voltage that is acting in the opposite direction to another voltage -for example, if we consider the direction in which a battery's voltage (E) to be acting to be 'positive', then any resulting voltage drop (V) will be acting in the 'negative' direction -i.e. E - V = 0 (i.e. the algebraic sum of the voltages around that circuit is zero).
In the same way, we can describe current as being 'positive' or 'negative' in the sense of its direction. For example, if one current (I1) is approaching a junction, and two currents (I2 and I3) are leaving that junction, we can write: I1 - I2 - I3 = 0 (i.e. the algebraic sum of the currents at that junction is zero).
Unfortunately, this doesn't specifically answer your question which, unfortunately, is rather confusing and needs to be rephrased.
Wiki User
∙ 11y ago
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How is it possible to measure negative current?
The term, 'negative current' simply refers to the sense or direction of a current compared with an assumed, standard, direction. For example, in the case of a battery, we normally assume that current leaves its positive terminal and enters its negative terminal (assuming conventional flow), and this is considered its 'positive direction'. However, if that battery were to be connected to a battery charger, the actual current would flow in the opposite sense to the assumed current direction and, so, it would be considered to be a 'negative' current.So, the simple answer is, yes, we can measure a 'negative current' by using an ammeter. In the case of d.c., it may be necessary to reverse the connections to that ammeter to ensure that it reads upscale.
What is breakover voltage?
forward-breakover voltage - the voltage at which a device enters the forward-blocking region. The voltage at which the SCR enters the forward-condition region. The value of Vbr(f) is maximum when (Ig=current in gate) Ig=0 and is designate Vbr(f0). When the gate current is increased, Vbr(f) decrease and is designated Vbr(f1), Vbr(f2), and so on, for increasing steps in gate current (Ig1, Ig2, and so on).
What kind of transformer is used to change the voltage of electric current in transmission lines before it enters houses in a neighborhood?
It's called a 'distribution transformer', as opposed to a 'power transformer' which is used in the transmission and primary-distribution electrical systems.
What happens if reactive power enters the system?
Reactive power entering the system will increase the system voltage.
Is it true that in a motor electrical current enters through the brushes?
yes
What is a positive or negative pole of an electrochemical cell?
They are called the electrodes or terminals. The parts of a cell where current leaves and enters the cell. The cathode is the positive, the anode is the negative.
Does resistance depend on whether the current leaves or enters the negative terminal?
No, resistance of a wire depends only on its nature, length and area.(R=pL/A) . It is independent on whether the current leaves or enters the negative terminals. By the way, current always flows from negative terminal of battery to its positive terminal,conventional current is nothing. But this is beyond the scope of the question!
How is it possible to measure negative current?
The term, 'negative current' simply refers to the sense or direction of a current compared with an assumed, standard, direction. For example, in the case of a battery, we normally assume that current leaves its positive terminal and enters its negative terminal (assuming conventional flow), and this is considered its 'positive direction'. However, if that battery were to be connected to a battery charger, the actual current would flow in the opposite sense to the assumed current direction and, so, it would be considered to be a 'negative' current.So, the simple answer is, yes, we can measure a 'negative current' by using an ammeter. In the case of d.c., it may be necessary to reverse the connections to that ammeter to ensure that it reads upscale.
What is breakover voltage?
forward-breakover voltage - the voltage at which a device enters the forward-blocking region. The voltage at which the SCR enters the forward-condition region. The value of Vbr(f) is maximum when (Ig=current in gate) Ig=0 and is designate Vbr(f0). When the gate current is increased, Vbr(f) decrease and is designated Vbr(f1), Vbr(f2), and so on, for increasing steps in gate current (Ig1, Ig2, and so on).
What is forward breakover voltage?
forward-breakover voltage - the voltage at which a device enters the forward-blocking region. The voltage at which the SCR enters the forward-condition region. The value of Vbr(f) is maximum when (Ig=current in gate) Ig=0 and is designate Vbr(f0). When the gate current is increased, Vbr(f) decrease and is designated Vbr(f1), Vbr(f2), and so on, for increasing steps in gate current (Ig1, Ig2, and so on).
How is the plus and minus voltage sign for resistance voltage drops for battery voltages and currents be determined?
The plus and minus voltage sign for resistance voltage, drops for battery voltages, and drops for currents is determined by convention. You can use whatever method you want - so long as your use is consistent, your analytical results will be correct for you.The commonly accepted convention, however, is best. This way, other people reviewing your results will not be confused unless, of course, they use an atypical convention.Electric current flow is electron flow. The battery terminal marked "negative", or the cathode, is the source of electrons, and those electrons are drawn to, and flow towards, the "positive" terminal, or anode.Consider a simple circuit, consisting of a battery in series with a resistor. Draw the battery on the left, with the anode up. Draw the resistor on the right. Connect the anode to the top of the resistor, and the cathode to the bottom of the circuit. (Actually, this is also a parallel circuit, with the battery in parallel with the resistor. It depends on how you see it, because this is a simple circuit.)Current flows out of the bottom (cathode, negative) battery terminal, into the bottom of the resistor, up through the resistor to its top, over to the left, and into the top (anode, positive) battery terminal, and down through the battery, completing the circuit at the cathode. This is counter-clockwise, if you have drawn the circuit as stated.If you place a voltmeter across the battery, you will see that the anode (top) is more positive than the cathode. If you place a voltmeter across the resistor, you will see that the top is more positive than the bottom. It does not matter if you measure across the battery or the resistor, the voltage will be the same. If you place the voltmeter across the wire on the bottom, or across the wire on the top, you will see that the voltage is zero.With the preliminaries out of the way, now to the convention.Current flow is counter-clockwise, from cathode to anode. If you were to draw a current arrow, you could draw it counter-clockwise, down through the battery and up through the resistor. You would label the first point that the current encounters (the bottom of the resistor) as negative, or minus. As the current goes through the resistor, it becomes more positive, so you would label the top of the resistor positive, or plus. Go over to the anode. That is also plus. The current is made more negative due to the battary being a source, rather than a load, so the cathode is minus.These pluses and minuses are relative to each other, and they are also relative to some common reference point, said point by convention being the cathode. In this simple circuit, there is only one point that has any voltage different than the cathode, and that is the anode, so this distinction might be vague.Consider then, the case where the resistor is actually two resistors in series. Again, the bottom resistor starts minus on its connection to the cathode, it becomes more positive as the current goes up, making the top of the bottom resistor plus. The bottom of the top resistor is minus, because current is flowing into it, and it becomes more positive as the current goes up, with the top of the top resistor plus.When you measure voltage across an element, you see the voltage for that element. If, instead, you measure the voltage relative to the common reference point, and there is more than one element between the voltmeter's leads, you add up the voltage rises or drops to figure out what to expect. In fact, this is the basis for Kirchoff's voltage law - that the signed sum of the voltage drops around a series circuit always adds up to zero.So, this preliminary convention is that current flow leaves the minus terminal of a voltage or current source, and enters the minus terminal of a voltage or current load. It then enters the plus terminal of a voltage or current source, and leaves the plus terminal of a voltage or current load.Now, to confuse you, another convention states that current flows from plus to minus, not from minus to plus. This means that current leaves the plus terminal of a source, and enters the plus terminal of a load, and it enters the minus terminal of a source and leaves the minus terminal of a load.It does not really matter which convention you use. The positions of the plus and minus signs will be the same - its just that the current arrow will point in the opposite direction - in this example, clockwise instead of counter-clockwise. What is important is to be consistent in your use of the plus or minus sign as the current enters and leaves a source or a load.The convention of current flow is arbitrary. So long as you are consistent in your application, you will get the correct results.It is generally accepted that current flow is electron flow, which means that current flows from the negative side of a voltage or current source towards the positive side.Often, however, current is considered to flow from positive to negative. While this makes perception in circuit analysis more straightforward, it does not change the analytical results.
Why do neuron sodium ions move from outside to inside the ason when an action potential travls along the axon?
Sodium is a positive ion. As it enters the cell the sodium influx raises the membrane potential (voltage) in that area. By doing this at many different stages along the axon one after the other, this positive current flows down the axon as an action potential, transferring nerve impulses from one neurone to the other.
How are step-up and step-down transformers used in the transmission of electric current from the electric company to homes?
(This is what my teacher said, I wrote this down in my notes) The answer is, Step-up transformers are used to increase the voltage of an electric current before it is sent out over transmission lines from the electric company. Step-down transformers are used to reduce the voltage of current from high-voltage transmission lines before it enters homes and businesses. Some devices, such as televisions, contain step-up transformers that increase the voltage once again.
How are step up and step down transformations used in transmission of electric current from electric company to homes?
(This is what my teacher said, I wrote this down in my notes) The answer is, Step-up Transformers are used to increase the voltage of an electric current before it is sent out over transmission lines from the electric company. Step-down transformers are used to reduce the voltage of current from high-voltage transmission lines before it enters homes and businesses. Some devices, such as televisions, contain step-up transformers that increase the voltage once again.
Zener knee current?
Not 100% sure, but I believe it's the reverse current at which a Zener diode enters breakdown. There is also the Zener max current which refers to the current that must not be exceeded if you do not wish to damage the device and also the Zener test current at which the Zener Voltage is measured. The test current usually lies somewhere (roughly halfway) between the knee and max current.
What is meant by the Geiger Muller region in the operation of a Geiger counter?
The Geiger-Müller region is the area on the performance curve of a Geiger-Müller (GM) tube where the voltage (or difference of potential, if you prefer) between the inner wire (the anode) and the outer case (the cathode) is sufficiently high to cause a current avalanche when any "substantial" unit of ionizing radiation (either particulate or electromagnetic) enters the detector. So much of the gas in the tube is ionized, and so many of the ions have moved in a given ionizing event that increasing the voltage won't affect any increase in this so-called avalanche current. Even increases of differential voltage in the range of hundreds of volts won't substantially alter the performance of the tube. This region, the one where current avalanches and no increase in current can be had by further increasing the voltage, is the Geiger-Müller region. This unit of ionizing radiation will ionize enough of the gas inside the tube that when the ions of gas move toward the electrodes (positive toward the negative and negative toward the positive), they will ionize more gas in the tube until much or most of the gas is ionized and moving. This will create a big "pulse" or a "current shot" or an avalanche of current that can be detected by support circuits in the electronics package that supports the GM tube. Additionally, the large-scale involvement of much of the gas in its ionized form to support this current flow will eventually insulate the anode with a big positive charge. The effect will be to "cut off" the tube and force it to "reset" or "un-ionize" throughout. This will restore conditions so that another pulse will again cause the same chain of events resulting in a "click" on counter. The electronics package records a "pulse" or a "count" of ionizing radiation, as it was designed to do. Links can be found below.
What is meant by the Geiger-Muller region in the operation of a Geiger counter?
The Geiger-Müller region is the area on the performance curve of a Geiger-Müller (GM) tube where the voltage (or difference of potential, if you prefer) between the inner wire (the anode) and the outer case (the cathode) is sufficiently high to cause a current avalanche when any "substantial" unit of ionizing radiation (either particulate or electromagnetic) enters the detector. So much of the gas in the tube is ionized, and so many of the ions have moved in a given ionizing event that increasing the voltage won't affect any increase in this so-called avalanche current. Even increases of differential voltage in the range of hundreds of volts won't substantially alter the performance of the tube. This region, the one where current avalanches and no increase in current can be had by further increasing the voltage, is the Geiger-Müller region. This unit of ionizing radiation will ionize enough of the gas inside the tube that when the ions of gas move toward the electrodes (positive toward the negative and negative toward the positive), they will ionize more gas in the tube until much or most of the gas is ionized and moving. This will create a big "pulse" or a "current shot" or an avalanche of current that can be detected by support circuits in the electronics package that supports the GM tube. Additionally, the large-scale involvement of much of the gas in its ionized form to support this current flow will eventually insulate the anode with a big positive charge. The effect will be to "cut off" the tube and force it to "reset" or "un-ionize" throughout. This will restore conditions so that another pulse will again cause the same chain of events resulting in a "click" on counter. The electronics package records a "pulse" or a "count" of ionizing radiation, as it was designed to do. Links can be found below.
