The voltage source provides voltage. The current source provides currents. I'm confused why there is current with the circuit which has only voltage source?
2007-02-12 06:28:06 · 8 answers · asked by Kari *** 1 in Science & Mathematics ➔ Engineering
So, there is actually current is flowing all the time???
2007-02-12 06:45:38 · update #1
A better definition of an (ideal) voltage source is: a device which maintains always the same voltage across its terminals, no matter how high may be the current it has to supply. Likewise, an ideal current source is that which supplies always the same current to anything connected to its terminals, irrespective of how high has to be the voltage developed to ensure this is so.
Real sources can only approximate this behavior ; for example, an actual voltage source (a storage battery, say) supplies a constant voltage up to certain point. If current increases beyond this point, terminal voltage across the source will drop somewhat. A real voltage source has always some internal impedance. As you increase current, at some value the effect of this internal impedance starts to be noticeable.
Analogously, as you increase the value of the impedance connected to a real current source, a point will be reached at which the source will not be able to develop the high voltage required across its terminals in order to keep current constant.
The above discussion should have made clear that a voltage source can --and does-- deliver current; in addition, it does so keeping voltage across its terminals reasonably constant.
A current source tries to keep current through itself reasonably constant, even if this implies having to adjust terminal voltage over a very wide range of values, according to the load connected to it.
Only an infinitely high (in ohms) load will draw no current from a voltage source, i.e., an open-circuit. Otherwise, a current will flow; its intensity ultimately depends on two factors: voltage put out by the source, --assumed constant-- and load impedance. That is, if you connect a 12 V source to a 120 Ω resistor, a current equal to 12/120 = 0.1 A will flow.
In contrast, only a short-circuit can prevent a current source to develop some voltage across its terminals. Otherwise, there will be a terminal voltage which ultimately depends --again-- on two factors: current, which is already known, and load impedance. The same 120 Ω resistor, connected to a 1 A current source, will develop a terminal voltage of 120 V.
Hope this will help.
14/2/2007 update.
Sure. That's what I've trying to say, all the time. In fact, a voltage source can be compared to a water pump, or rather, a constant-pressure water pump; if the pressure is there, usually water flows. Unless stopped by a (closed) valve, which can be compared to a switch. Or a totally clogged pipe, which is like an open circuit, or an infinitely high resistance (high in ohms, not height).
2007-02-12 07:13:06 · answer #1 · answered by Jicotillo 6 · 0⤊ 0⤋
A voltage source is designed to hold the voltage steady, no matter what the load is, as long as the load does not draw more current than the power supply can generate. So, the current can vary, while the voltage is held constant. Most power supplies use a constant voltage.
A current source is designed to hold the current steady. The voltage will fluctuate while the current stays constant. But the voltage will be limited to a certain maximum value. Otherwise, it will constantly arc between the terminals when you remove the load. If you short circuit it, then it will still flow the same amount of current.
2007-02-12 07:11:06 · answer #2 · answered by vrrJT3 6 · 0⤊ 0⤋
You are correct in that the voltage source provides voltage - which can be thought of as a potential or force which is capable of causing the electrons to flow from the negative electrode to the positive electrode. Until these two poles are connected in a circuit, no current will flow. When the positive electrode is connected through a completed circuit to the negative electrode, the voltage potential will force electrons through the circuit. The current is a measure of the actual flow of these electrons and is measured in Amps (I). The amount of this current is determined by how much potential is applied (E) and how much resistance (R) has to be overcome.
The relationship is called Ohms Law and is E=IR, the voltage equals the amperage times the resistance. It is also written as R=E/I or I=E/R.
Well, that's about it in a nut shell.
2007-02-12 07:10:28 · answer #3 · answered by LeAnne 7 · 0⤊ 0⤋
Consider the voltage is the pressure to move the current. Then there is resistance which can dissipate the energy across the resistance. The resistors is like u putting a crimp in the hose.
Now to Electrical the voltage pushes the electrons through the circuit. Good connections do not heat. Bad connections create heat.
2007-02-12 08:27:08 · answer #4 · answered by JOHNNIE B 7 · 0⤊ 0⤋
Wow. Voltage induces current through a resistance. So they are proportionate. Did you think you could have a circuit with voltage and no current, or vice versa? That's like having a river that doesn't flow. How would the river be there if there wasn't flow? Nice that someone typed out a novel for you to try to understand the topic though....sheesh. Hope you got your bifocals on.
2007-02-13 01:14:32 · answer #5 · answered by joshnya68 4 · 0⤊ 0⤋
It refers to Output Inverter where The voltage and current go in the same way. Two names for one thing, Inverter Output No refers for regulating current or voltage it refers to output of inverters
2016-05-24 01:28:39 · answer #6 · answered by Anonymous · 0⤊ 0⤋
it is simple.
V = voltage
I = current
R = resistence
I = V/R
So closing a voltage generator on a resistance you can optanin current on the resistance.
And closing a current generator on a resistance you can obtain a voltage on the resistance.
2007-02-12 06:37:41 · answer #7 · answered by Marco 2 · 0⤊ 0⤋
extremely tough problem. look with bing and yahoo. that could help!
2014-11-14 20:18:26 · answer #8 · answered by brian 3 · 0⤊ 0⤋