Capacitor and Inductor Using PSpice

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Capacitor and Inductor Using PSpice
18/8/09
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Modeling Capacitor

• We have to put a big resistor (e.g. 1G) across
  a capacitor to provide a DC current path to
  ground.
• This is because a capacitor acts as open circuit
  to DC (No DC path is provided by capacitor).

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Modeling Inductor
R1
L1
V1

• We have to put a small resistor (e.g. 1u) in
  series with an inductor to avoid the DC current
  in the inductance infinitely large.
• This is because an inductor acts as a short
  circuit to DC.

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Modeling PWL Sources (I or V)
R1
V1
L1
or
I1
or
V1
100
I1 0 1 PWL(0,0)(2ms,100)
50
V1 1 0 PWL(0,0)(2ms,100)
or
0
0s
0.5ms
1.0ms
1.5ms
2.0ms
2.5ms
3.0ms
3.5ms
4.0ms

Time
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To Set Analysis Request

• Type of Analysis Transient
• General format
• .TRAN TSTEP TSTOP ltTSTART ltTMAXgtgt
• Example
• .TRAN 5u 5m 0 5u or .TRAN 5m 5 0 5m

• TSTEP and TMAX determine the time increment. To
  make the thing simpler, set the same values for
  both TSTEP and TMAX. If the time increment is not
  small enough, the plot will not be smooth.
• PSpice will generate data from 0 (TSTART) to 5ms
  (TSTOP) with the time increment of 5u (TSTEP or
  TMAX). So, at least 1000 data will be generated.

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To Get Add Trace Expression

V(1)
ic(t)
Capacitor Voltage
ic(t)
I(C1)
Capacitor Current
V(1)I(C1)
vc(t)?ic(t)
Capacitor Power
Capacitor energy
S(V(1)I(C1))
What you will really type in the trace
expression box depends on your own netlist
description.
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EXAMPLE 6-1
300
Capacitor Voltage
200
Capacitor Current
100
0
0s
0.5ms
1.0ms
1.5ms
2.0ms
2.5ms
3.0ms
3.5ms
4.0ms

Time
V(1)
I(C1)
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EXAMPLE 6-2
9
EXAMPLE 6-3
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EXAMPLE 6-4
V(1)
I(L1)
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Using Toggle Cursor
Probe toolbar
Toggle Cursor
1. By clicking Toggle Cursor toolbar, we will get
access to Cursor toolbar.
Cursor Peak to get the peak point on the plot.
Mark label to mark the data point on the plot.
Cursor Search to search data point on the plot.
For example, by typing SFXval(3s) in Search
Command box, the Probe Cursor will point at x3s.
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Using Toggle Cursor
Toggle Cursor Toolbar is used to get access to
data points on a plot through the Probe Cursor.
We can toggle the display of the Probe cursor on
and off by clicking the Toggle Cursor toolbar.
2. Also, by clicking the cursor toolbar, we will
be given access to two cursors. One of the
cursors is controlled by the left mouse button
A1 (x,y) and one is controlled by the right
mouse button A2 (x,y). A small window labeled
Probe Cursor gives the values at each of the
cursors as well as the difference between them.
We can also finely move the cursors by using
left-arrow and right-arrow on the keyboard.
3. Marking a specific voltage/current level. By
clicking Mark Label toolbar will label the
specific point on the plot, which is pointed to
by the cursor that was last moved.