A current controlled voltage source produces a voltage that is linearly proportional to a current. A resistor has the same behavior. And the gain for a CCVS is measured in ohms, which is the same unit that measures a resistor. So what is the difference between them? Is a resistor just a kind of CCVS (and I guess also a VCCS) and if so, how does it differ from an ideal CCVS?
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\$\begingroup\$ One nitpick for better understanding - the relation between control current and produced voltage does not have to be linearly proportional as your ? states, but linearity is often preferred in applications and models of course. \$\endgroup\$– EwokNightmaresCommented Apr 22, 2014 at 20:43
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\$\begingroup\$ A CCVS is a two-port or four-terminal network. A resistor is a one-port or two-terminal network. \$\endgroup\$– alejnavabCommented Feb 9, 2022 at 4:28
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7 Answers
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A resistor is a passive component. A current controlled voltage source is an active component i.e. the voltage will remain proportional to the current controlling it regardless of what else is connected to the source (ideally).
answered Apr 22, 2014 at 20:33
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\$\begingroup\$ Few more differences. Unlike real resistors CCVS may have negative resistance. Noise characteristics would also be different -- regular resistors have inherent Johnson (AKA thermal) noise which CCVS may not replicate exactly. \$\endgroup\$– ArtemBCommented Apr 22, 2014 at 22:41
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A nice graphic answering one half of the question
I don't remember the source of this, since I have stored on my HD
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\$\begingroup\$ That reminds me of XKCD (except for the drawing style) - at least in terms of brilliance! \$\endgroup\$ Commented Apr 23, 2014 at 9:32
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The following two ideal circuit elements have identical terminal characteristics and are thus indistinguishable:
simulate this circuit – Schematic created using CircuitLab
Thus, if the controlling variable of a CCVS is the current through the CCVS, the CCVS is indistinguishable from a resistor where the gain of the CCVS is the resistance.
If the controlling variable of a CCVS is the current through another circuit element, the gain is the transresistance.
answered Apr 22, 2014 at 21:00
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A resistor produces a voltage that is linearly proportional to the current that flows into it. Moreover the polarity of the voltage is fixed too, you can't have current flowing in a resistor from A to B and have \$V_B>V_A\$.
A CCVS can be controlled by any current in the network, possibly the one that flows through it but again, this time you get the freedom to choose the voltage polarity.
answered Apr 22, 2014 at 20:08
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A circuit that is called voltage "SOURCE" must be able to deliver the output to any connected load - otherwise it is not really a "source". Hence, it must have a very small source resistance (ideal: zero). This is the main feature of an active CCVS.
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A resistor controls current in same branch. The dependent sources show interdependence of different branches. i.e current through one branch controls voltage through some other branch or current through one branch controls current through some other branch. So, dependent sources can be generalized as the concept of resistance but they are not same as resistance.
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Have a look at the very end of this IEEE paper.
https://leachlegacy.ece.gatech.edu/papers/superpos.pdf
Since a resistor can be considered as a voltage controlled current source with the current source equal to the voltage across the resistor multiplied by 1/R, or as a current controlled voltage source with the parameter R
A practical example of a current controlled voltage source (CCVS) would be the I*R voltage drop across a current controlled low-side sense resistor.
A practical example of a voltage controlled current source (VCCS) would be this
https://e2e.ti.com/blogs_/b/analogwire/posts/designing-with-linear-thermistors
