Avionics News September 2019 - 46

series
B Y

T H O M A S

I N M A N

ELI Returns
I

n the March issue of Avionics News, this
column examined inductors and capacitors in
a direct current environment. You may recall
our mnemonic: ELI the ICE man. For inductors, the
principles were relatively simple and can be summarized
as follows:
1.	 All wire has inductance, because the flow of
current induces a magnetic field.
2.	 Forming wire into a coil increases inductance.
3.	 After voltage is applied, there is a delay, or lag,
before current begins to flow. (ELI)
4.	 Current will continue to (or attempt to) flow
for a moment after voltage is removed.
5.	 Inductances in series add to a total inductance.
6.	 Inductances in parallel equal the reciprocal of
the sum of the reciprocals.
When an inductor is placed into an AC circuit, items
three and four above are of particular interest. We
reported in June that the voltage in an AC circuit is
changing constantly. This complicates matters in an AC
circuit with inductors.
Let's start by revisiting resistance, which I wrote
about in January and February. Typically, resistors are
made of carbon and resist the flow of current through
them, causing a voltage drop. Implied last winter, but
not mentioned specifically, resistors are passive. They
don't resist actively; they merely sit there passively,
dissipating heat. Inductors are a different case. An
46

avionics news

*

september

2019

inductor will have little resistance. Instead, an inductor
reacts.
As stated in item three above, any time voltage is
applied to an inductor, there is a lag before current
flows. In June, we examined how an AC waveform can
be divided into 360 degrees. Figure 1 shows a voltage
curve and a current curve in an inductive circuit. Notice
there is a lag of 90 degrees. As shown in Figure 1, at the
180 degree point, the voltage has switched polarity, but
the current is still flowing in the original direction.
In July, we noted how moving a wire through a
magnetic field induces current flow. Of course, the same
is true if we move a magnetic field past a wire. Since
the current is constantly increasing and decreasing, so
is the magnetic field. As a result, the magnetic flux

Figure 1: The relationship of voltage and current in a purely
inductive circuit.



Avionics News September 2019

Table of Contents for the Digital Edition of Avionics News September 2019

No label
Avionics News September 2019 - No label
Avionics News September 2019 - Cover1
Avionics News September 2019 - Cover2
Avionics News September 2019 - 1
Avionics News September 2019 - 2
Avionics News September 2019 - 3
Avionics News September 2019 - 4
Avionics News September 2019 - 5
Avionics News September 2019 - 6
Avionics News September 2019 - 7
Avionics News September 2019 - 8
Avionics News September 2019 - 9
Avionics News September 2019 - 10
Avionics News September 2019 - 11
Avionics News September 2019 - 12
Avionics News September 2019 - 13
Avionics News September 2019 - 14
Avionics News September 2019 - 15
Avionics News September 2019 - 16
Avionics News September 2019 - 17
Avionics News September 2019 - 18
Avionics News September 2019 - 19
Avionics News September 2019 - 20
Avionics News September 2019 - 21
Avionics News September 2019 - 22
Avionics News September 2019 - 23
Avionics News September 2019 - 24
Avionics News September 2019 - 25
Avionics News September 2019 - 26
Avionics News September 2019 - 27
Avionics News September 2019 - 28
Avionics News September 2019 - 29
Avionics News September 2019 - 30
Avionics News September 2019 - 31
Avionics News September 2019 - 32
Avionics News September 2019 - 33
Avionics News September 2019 - 34
Avionics News September 2019 - 35
Avionics News September 2019 - 36
Avionics News September 2019 - 37
Avionics News September 2019 - 38
Avionics News September 2019 - 39
Avionics News September 2019 - 40
Avionics News September 2019 - 41
Avionics News September 2019 - 42
Avionics News September 2019 - 43
Avionics News September 2019 - 44
Avionics News September 2019 - 45
Avionics News September 2019 - 46
Avionics News September 2019 - 47
Avionics News September 2019 - 48
Avionics News September 2019 - 49
Avionics News September 2019 - 50
Avionics News September 2019 - 51
Avionics News September 2019 - 52
Avionics News September 2019 - 53
Avionics News September 2019 - 54
Avionics News September 2019 - 55
Avionics News September 2019 - 56
Avionics News September 2019 - 57
Avionics News September 2019 - 58
Avionics News September 2019 - 59
Avionics News September 2019 - 60
Avionics News September 2019 - 61
Avionics News September 2019 - 62
Avionics News September 2019 - 63
Avionics News September 2019 - 64
Avionics News September 2019 - 65
Avionics News September 2019 - 66
Avionics News September 2019 - 67
Avionics News September 2019 - 68
Avionics News September 2019 - 69
Avionics News September 2019 - 70
Avionics News September 2019 - 71
Avionics News September 2019 - 72
Avionics News September 2019 - Cover3
Avionics News September 2019 - Cover4
http://www.brightcopy.net/allen/avne/57-11
http://www.brightcopy.net/allen/avne/57-10
http://www.brightcopy.net/allen/avne/57-9
http://www.brightcopy.net/allen/avne/57-8
http://www.brightcopy.net/allen/avne/57-7
http://www.brightcopy.net/allen/avne/57-6
http://www.brightcopy.net/allen/avne/57-5
http://www.brightcopy.net/allen/avne/57-4
http://www.brightcopy.net/allen/avne/57-3
http://www.brightcopy.net/allen/avne/57-2
http://www.brightcopy.net/allen/avne/57-1
http://www.brightcopy.net/allen/avne/56-12
http://www.brightcopy.net/allen/avne/56-11
http://www.brightcopy.net/allen/avne/56-10
http://www.brightcopy.net/allen/avne/56-9
http://www.brightcopy.net/allen/avne/56-8
http://www.brightcopy.net/allen/avne/56-7
http://www.brightcopy.net/allen/avne/56-6
http://www.brightcopy.net/allen/avne/56-5
http://www.brightcopy.net/allen/avne/56-4
http://www.brightcopy.net/allen/avne/56-3
http://www.brightcopy.net/allen/avne/56-2
http://www.brightcopy.net/allen/avne/56-1
http://www.brightcopy.net/allen/avne/55-12
http://www.brightcopy.net/allen/avne/55-11
http://www.brightcopy.net/allen/avne/55-10
http://www.brightcopy.net/allen/avne/55-9
http://www.brightcopy.net/allen/avne/55-8
http://www.brightcopy.net/allen/avne/55-7
http://www.brightcopy.net/allen/avne/55-6
http://www.brightcopy.net/allen/avne/55-5
http://www.brightcopy.net/allen/avne/55-4
http://www.brightcopy.net/allen/avne/55-3
http://www.brightcopy.net/allen/avne/55-02
http://www.brightcopy.net/allen/avne/55-01
http://www.brightcopy.net/allen/avne/54-12
http://www.brightcopy.net/allen/avne/54-11
http://www.brightcopy.net/allen/avne/54-10
http://www.brightcopy.net/allen/avne/54-9
http://www.brightcopy.net/allen/avne/54-8
http://www.brightcopy.net/allen/avne/54-7
http://www.brightcopy.net/allen/avne/54-6
http://www.brightcopy.net/allen/avne/54-5
http://www.brightcopy.net/allen/avne/54-4
http://www.brightcopy.net/allen/avne/54-3
http://www.brightcopy.net/allen/avne/54-2
http://www.brightcopy.net/allen/avne/54-1
http://www.brightcopy.net/allen/avne/53-12
http://www.brightcopy.net/allen/avne/53-11
http://www.brightcopy.net/allen/avne/53-10
http://www.brightcopy.net/allen/avne/53-9
http://www.brightcopy.net/allen/avne/53-8
http://www.brightcopy.net/allen/avne/53-7
http://www.brightcopy.net/allen/avne/53-6
http://www.brightcopy.net/allen/avne/53-5
http://www.brightcopy.net/allen/avne/53-4
http://www.brightcopy.net/allen/avne/53-3
http://www.brightcopy.net/allen/avne/53-2
http://www.brightcopy.net/allen/avne/53-1
http://www.brightcopy.net/allen/avne/52-12
http://www.brightcopy.net/allen/avne/52-11
http://www.brightcopy.net/allen/avne/52-10
http://www.brightcopy.net/allen/avne/52-9
http://www.brightcopy.net/allen/avne/52-8
https://www.nxtbook.com/allen/avne/52-7
https://www.nxtbook.com/allen/avne/52-6
https://www.nxtbook.com/allen/avne/52-5
https://www.nxtbook.com/allen/avne/52-4
https://www.nxtbook.com/allen/avne/52-3
https://www.nxtbook.com/allen/avne/52-2
https://www.nxtbook.com/allen/avne/52-1
https://www.nxtbook.com/allen/avne/51-12
https://www.nxtbook.com/allen/avne/51-11
https://www.nxtbook.com/allen/avne/51-10
https://www.nxtbook.com/allen/avne/51-9
https://www.nxtbook.com/allen/avne/51-8
https://www.nxtbook.com/allen/avne/51-7
https://www.nxtbook.com/allen/avne/51-6
https://www.nxtbook.com/allen/avne/51-5
https://www.nxtbook.com/allen/avne/51-4
https://www.nxtbook.com/allen/avne/51-3
https://www.nxtbook.com/allen/avne/51-2
https://www.nxtbook.com/allen/avne/51-1
https://www.nxtbook.com/allen/avne/50-12
https://www.nxtbook.com/allen/avne/50-11
https://www.nxtbook.com/allen/avne/50-10
https://www.nxtbook.com/allen/avne/50-9
https://www.nxtbook.com/allen/avne/50-8
https://www.nxtbook.com/allen/avne/50-7
https://www.nxtbook.com/allen/avne/50-6
https://www.nxtbook.com/allen/avne/50-5
https://www.nxtbook.com/allen/avne/50-4
https://www.nxtbook.com/allen/avne/50-3
https://www.nxtbook.com/allen/avne/50-2
https://www.nxtbook.com/allen/avne/50-1
https://www.nxtbook.com/allen/avne/49-12
https://www.nxtbook.com/allen/avne/49-11
https://www.nxtbook.com/allen/avne/49-10
https://www.nxtbook.com/allen/avne/49-9
https://www.nxtbook.com/allen/avne/49-8
https://www.nxtbook.com/allen/avne/49-7
https://www.nxtbook.com/allen/avne/49-6
https://www.nxtbook.com/allen/avne/49-5
https://www.nxtbook.com/allen/avne/49-4
https://www.nxtbook.com/allen/avne/49-3
https://www.nxtbook.com/allen/avne/49-2
https://www.nxtbook.com/allen/avne/49-1
https://www.nxtbook.com/allen/avne/48-12
https://www.nxtbook.com/allen/avne/48-11
https://www.nxtbookmedia.com