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What is the symbol for current? Current intensity is often referred to simply as current. Eleuterio Butuc Explainer. What happens to current when voltage increases? Ohm's law states that the electrical current I flowing in an circuit is proportional to the voltage V and inversely proportional to the resistance R. Therefore, if the voltage is increased , the current will increase provided the resistance of the circuit does not change. Karishma Umrigar Explainer. What does the voltage tell you?
Voltage is the measure of specific potential energy potential energy per unit charge between two locations. When a voltage source is connected to a circuit, the voltage will cause a uniform flow of charge carriers through that circuit called a current. Johathan Ganuza Pundit. Why current is low when voltage is high? Why High Voltage.
Bonka Palmes Pundit. How do you create voltage? When a wire made of an electrically conductive material one containing atoms whose outer electrons can move easily from one atom to the next passes through a magnetic field, the magnetic field knocks electrons loose from their atoms to create a difference in electric potential, or voltage , in the conductor. Soumiya Gohrke Pundit. What affects voltage? The main factors that affect chemical reactions are Temperature, Surface area and Concentration.
By increasing the amount of collisions per second the amount of volts should also be affected by the increased collision rates too. Can you have negative voltage? A negative voltage is a relative excess of electrons compared to some other point. If 0 V is no voltage. Negative voltage is an excess of electrons and positive voltage is a deficiency of electrons. Gezabel Scheller Pundit.
What is a voltage for kids? Voltage is an electric force that causes free electrons to move from one atom to another. Just like water needs pressure to force it through a hose, electrical current needs some force to make it flow. A volt is the measure of electric pressure. Voltage is usually supplied by a battery or a generator. Sindia Heidenbluth Teacher. The moment your component starts drawing less current, the voltage shoots up and kills it. You need something better — the voltage should not depend on the load current, at least not much.
The next simplest fix that comes to your head is the voltage divider. This needs two resistors, but hey, if they can be squeezed in they may as well work. Another nagging problem — the moment your component starts drawing too much current, the output of the divider sags — the top resistor is not able to keep up with the current demand. You could fix this by lowering the resistor values, but that would make the two resistors draw too much current, probably ruining your current budget and getting too hot with the immediate risk of failure.
What else could be done? Of course, you had to slog through hours of lectures on those! Why not add an NPN transistor as a voltage follower? Of course, this is an amplifier, it does not have the intelligence to auto-compensate. You could replace the bottom resistor of the voltage divider with a Zener diode , but the current required to properly bias a Zener against things like temperature coefficients and drift is almost as much as your component consumes — which is completely pointless.
Millions of EEEs around the world have been though similar periods of stress including me! Of course, not all problems are associated with dropping voltages, but similar situations are common is EEE labs everywhere! They keep getting better every day — some of them consume no more than a few nanoamps, that is a thousandth of a millionth of an amp!
Even better, others come with short circuit and overtemperature protection — making them foolproof. A voltage regulator is basically a beefed up emitter follower, like described above — a transistor connected to a stable reference that spits out a constant voltage, dropping the rest.
They also have a built in error amplifier, which samples the output voltage again through a divider , compares it with the reference voltage, calculates the difference, and drives the output transistor accordingly. This is far cry from a voltage divider, which faithfully replicates the input signal, though just a magnitude smaller. It is desirable to have a transistor with high gain, since power transistors are a huge pain to drive, with pathetic gains in the range of two digits.
Since these types require less current to drive, the overall current consumption decreases. This is supplemented by the fact that the voltage reference used internally also consumes very little current. The current that the regulator consumes to drive all this internal circuitry when the output is not loaded is called the quiescent current.
The lower the quiescent current, the better. Either one can put stress on your electronic components or can damage them severely, similar to how too much water pressure in a hose could cause the hose to burst. Although surge protectors do a fine job when dealing with fluctuations in voltage, you'll be better off unplugging your computer if a lightning storm is about to hit your neighborhood. Sign up for our Newsletter! Mobile Newsletter banner close.
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