current source and voltage source

hi,

Though i have pursued my circuit analysis course long back, i am not yet convinced with the knowledge i have gained. I have a very basic thing to ask, as written in the topic, the difference between Voltage Source and Current Source. Also, the differences between voltage and current if that is necessary... also...

I would prefer any references from the boks which u feel is too good for explaining rather than u explaining because, it takes more time and also, u know somewhat irritating to type long. I dont mean to say that i will not be satisfied with the replies u give me.... Also, I wanted to know more about the transient analysis, the RC time constants.. abt transformers, Two Port networks.. Though i have attained good grades in these subjects.. i feel i was more methodoical rather than conceptual in solving the problems. Given a proiblem though i may be in a postion to solve... i am not able to have a commanding position over the subject, as i would say, as i have in other subjects. So, any one pls spare some time to put in suggestions and also references to help me attain confidence .. pls...

regards,
arunmit168.

As far as i know it is just a matter of perspective. A physical source can be considered as either a voltage or a current source. Usually we consider a source as a current source if it has large internal resistance and as a voltage source if it has a small internal resistance. Remember that by (Millman's I think ) theorem you can replace a (non-ideal) voltage source with an equivalent current source (and conversely) in a circuit's analysis.

kgl_13gr is wrong, it is not about pestpective, you can'n use a voltage reference in a differential pair just because you need a virtual ground, or high resistance.

One thing to have on mind is what need your circuit, high or low impedance.

mmmmm let's see

A current source is the one that gives you a constant current, the voltage can vary depending on the circuit u connect the thing to.
Likewise a voltage source is the one that gives you a constant voltage, the current it gives you depends on the circuit u put, an example of this is a simple batery, the voltage is constant the current varies.

It is important to know the maximun current or voltage u can take from a source, current for voltage sources and voltage for current sources.

I hope i made myself clear.

brain79 said:

One thing to have on mind is what need your circuit, high or low impedance.

Click to expand...

yeh i could get u, abt the perspective. and, how do u relate the voltage source and the current source with that of the impedance... that is the point i needed.. actually. i am unable to link the various parameters... and moreover, ur answer reg. the impedance was the case when we formulate a circuit i suppose.

my question was given a circuit how to solve it... ok, anyway, i need to know abt the current source and voltage source before solving them. so, if your explanation could help me in explaining that, well and good. And, any references.

DarkJedi said:

I hope i made myself clear.

Click to expand...

No, I knew them already. I wanted a different explanation.... I dono how to tell....

kgl_13gr said:

Remember that by (Millman's I think ) theorem you can replace a (non-ideal) voltage source with an equivalent current source (and conversely) in a circuit's analysis.

Click to expand...

Again, the conversion of a voltage source to current source etc... are the methods.. they are theorems.. but the concept behind it i need that... i 2 knew all those theorems which are used in circuit analysis... nevertheless am void of concepts...

Also, i want to make sure that there is some underlying concept as i put it here,..... if there is none and if it is to be taken for granted i mean the theorems,.... then... well and good.. but again with less satisfaction...

regards,
arunmit168.

Voltge is like the pressure of water and current is like the flow of water. Voltage source means measure the pressure of water at that point and current source means measure the flow of water at that point rather than measure the pressure.

pico said:

Voltge is like the pressure of water and current is like the flow of water. Voltage source means measure the pressure of water at that point and current source means measure the flow of water at that point rather than measure the pressure.

Click to expand...

Thou ur analogy is good, it would be better if you could also give a reference. i would like to have a personal study for myself in addition to ur valuable replies... Does every electric circuit book contain this information... that means i am not able to get the info from the book.... coz.. i have more than 1... i have studied them 2....

regards,
arunmit168.

I think that Chapter # 1 of

Electronics Principle by Malvino

will help u . Check that.

my 4-20 ma out design

i want to produce 220 volt from the cars
battery which is 12 volt ,can you help me what kind of devices
to implement.
it should not consum lot

Sounds like you need a refresher on linear circuits.

Hi,

For the refresh Delay wrote about, look this well done site :

h**p://www.allaboutcircuits.com/vol_1/index.html

It starts from scratch (ohm's law), explain Thevenin's, Norton's and Millman's theorems and much more.

For current/tension sources see volume 1, chapter 10 :

https://www.allaboutcircuits.com/vol_1/chpt_10/9.html

* = t

Usually power supplies have a fixed or adjustable current limiting circuit built-in. A current source is simply a voltage supply operating at the current limit.
A simple example is with laser diodes. The strength of a laser depends on the current flowing through the diode. A diode allows current to flow in one direction, but has little restrictions on the current magnitude. It takes in as much current as it can possibly take until it burns out. The output voltage of the current supply is then approximately the saturation voltage of the diode.
Therefore, the current is fixed here but the voltage depends on the external circuit.

cn u get mr the solutions to problems given in microelectronics by millman and grebal.I m finding difficulty in solving. pls help me.

u can get enough idea from the book by william hayt and kemerly or by decarlo and lin.
the first book is available in this forum.

voltage source will have small series resistance
current source will have large parallel resistance