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- Newsgroups: sci.electronics
- Path: sparky!uunet!boulder!ucsu!tramp.Colorado.EDU!barr
- From: barr@tramp.Colorado.EDU (BARR DOUG)
- Subject: Re: Inductors
- Message-ID: <1992Nov16.174359.15810@ucsu.Colorado.EDU>
- Sender: news@ucsu.Colorado.EDU (USENET News System)
- Nntp-Posting-Host: tramp.colorado.edu
- Organization: University of Colorado, Boulder
- References: <Vc99TB2w165w@digsol.jpunix.com>
- Date: Mon, 16 Nov 1992 17:43:59 GMT
- Lines: 34
-
- In article <Vc99TB2w165w@digsol.jpunix.com> newton@digsol.jpunix.com (Michael Nichols) writes:
- >I'm getting started in electronics and have been reading about inductors.
- >Although it says that inductors resist change in voltage, it doesn't give
- >any distinct mathematical method for determining how much an inductor of
- >given inductance-rating will affect the waveform of the circuit. Could
- >somebody explain this to me?
- >
- >Mike Nichols
- >newton@digsol.jpunix.com
- Inductor rules:
- 1. An inductor is a short circuit to a DC voltage or current source.
- 2. v = L d (i) (voltage across an inductor equals L times the first
- dt derivative with respect to time of the current i)
-
- Doing this requires understanding calculus and simple differential equations.
- If you have the following simple circuit:
-
- -------------------------
- | |
- /\ i N \ v = L d i
- | / dt
- |_______________________|
-
-
- d is the first deviative with respect to time.
- dt
- t is the variable time, v is the voltage across the inductor,
- where N is an inductor, i is current, L is the inductance of the inductor
- in henrys, the funny \/ combination is an inductor. Now if i is sine(2*pi*f*t)
- (where f is some frequency), then v (the voltage across the inductor) is
- the first derivative of sine(2*pi*f*t). The first derivative of sine(2*pi*f*t)
- is 2*pi*f*cos(2*pi*f*t). Evaluate this for all time t from 0 to 2*pi, and
- plot i and v and notice the relation.
-
-