svg-schematic 0.7.0

Component Placement

In this example the resistor is placed without a location, and so its center is placed at the origin, (0, 0). You can then access the location of the center of the resistor using r.C, which is a XY-pair. That is passed to the capacitor using C=r.C with an extra parameter of xoff=75, meaning the center of the capacitor is horizontally offset by 75 units from center of the resistor. To give you a sense of how far 75 units is, the length of the resistor is 100 units. Positive horizontal offsets shift the location to the right, positive vertical offsets shift the location down. Finally, the inductor is placed 75 units to the right of the capacitor.

When specifying offsets, you can specify the x-offset using xoff, the y-offset using yoff, and you can specify both with off as a tuple. For example, off=(50,25) is equivalent to xoff=50, yoff=25.

Wires are added using an list of points, where each point is an XY-pair. In the simplest case, a line is run between each of the point specified. Thus, the first wire runs from r.p to l.p, where r is the resistor and r.p is the location of the p terminal of the resistor. l.p is the location of the positive terminal of the inductor. The second wire connects the negative pins.

Principle Coordinates

Each component is embedded in a tile, and each tile has 9 principle coordinate named C, N, NE, E, SE, S, SW, W, and NW which are short for center, north, northwest, eash, southeast, south, southwest, west and northwest.

When placing a component, you can give the location of any of the principle coordinates. And once placed, you can access the location of any of the principle coordinates. Thus, you can stack one component on top of another using:

c1 = Capacitor(name='C1')
c2 = Capacitor(name='C2', N=c1.S)

This places the north principle coordinate of c2 at the south principle coordinate of c1, which effectively stacks c1 directly over c2.

Pins as Coordinates

You can also specify and access the component pins. For example, with the resistor there are two terminals p and n.

The above example could also be given as:

c1 = Capacitor(name='C1')
c2 = Capacitor(name='C2', p=c1.n)

This places the p terminal of C2 at the n terminal of C1, so it is another way to stack C1 over C2.

Orientation

You can flip and rotate the components using the orient argument. Specifying v implies a vertical orientation, and h a horizontal orientation (a component is converted from vertical to horizontal with a -90 degree rotation. Adding | implies the component should be flipped along a vertical axis (left to right) and adding - implies the component should be flipped along a horizontal axis (up to down).

Name and Value

With most components you can specify a name, and with many components you can also specify a value. The text orientation will always be horizontal regardless of the component orientation. You can also specify nudge as a small number to adjust the location of the resulting text. For example:

from svg_schematic import (
    Schematic, Capacitor, Ground, Inductor, Resistor, Pin, Source, Wire
)
from inform import Error, error, os_error

try:
    with Schematic(
        filename = 'names.svg',
        background = 'none',
    ):
        vin = Source(name='Vin', value='1 V', kind='sine')
        Ground(C=vin.n)
        rs = Resistor(name='Rs', value='50 Ω', n=vin.p, xoff=25)
        Wire([vin.p, rs.n])
        c1 = Capacitor(name='C1', value='864 pF', p=rs.p, xoff=25)
        Ground(C=c1.n)
        l2 = Inductor(name='L2', value='5.12 μH', n=c1.p, xoff=25)
        Wire([rs.p, l2.n])
        c3 = Capacitor(name='C3', value='2.83 nF', p=l2.p, xoff=25)
        Ground(C=c3.n)
        l4 = Inductor(name='L4', value='8.78 μH', n=c3.p, xoff=25)
        Wire([l2.p, l4.n])
        c5 = Capacitor(name='C5', value='7.28 nF', p=l4.p, xoff=25)
        Ground(C=c5.n)
        rl = Resistor(name='Rl', value='50 Ω', p=c5.p, xoff=100, orient='v')
        Ground(C=rl.n)
        out = Pin(name='out', C=rl.p, xoff=50, w=2)
        Wire([l4.p, out.t])
except Error as e:
    e.report()
except OSError as e:
    error(os_error(e))

Kind

Many components allow you to specify kind, which allow you to choose a variant of the component symbol. They include

These are explained further later when the individual symbols are discussed.

Miscellany

There are a few things to note.

1. SVG coordinates are used, which inverts the y axis (more southern coordinates are more positive than the more northern coordinates).

2. Wires and components stack in layers, with the first that is placed going on the lowest layer. Most components contain concealers, which are small rectangles that are designed to conceal any wires that run underneath the components. This allows you to simply run a wire underneath the component rather than explicitly wire to each terminal, which can simply the description of the schematics. For this to work, the wire must be specified before the component. Also, the color of the concealers matches that of the background, so if you use no background, then you also lose the concealers.

3. Components are placed in invisible tiles. The unit size of a tile is 50. You have limited ability to specify the width and height of some components, and specifying the size as w=1, h=1 implies the tile will be 50x50. Most components have a size of 2×2 and so sit within a 100x100 tile. You need not specify the size as an integer.

4. When the schematic is used with Latex, you can use Latex formatting in the name and value. For example, you can specify: name=’$L_1$’. You should use raw strings if your string contains backslashes: value=r’$10 \mu H$’.

5. Components provide provide individual attributes for the location of each terminal. For example, the resistor, capacitor, and inductor components provide the p and n terminal attributes. The MOS component provides the d, g, and s terminal attributes. The diode component provides the a and c terminal attributes.

6. Components contain attributes for each of the 9 principal coordinates (C, N, NE, E, SE, S, SW, W, NW). For most components, these are the principal coordinates for the component’s tile. However, the source places its principal coordinates on the circle used to depict the source.

Placement Strategies

There are two basic approaches to placing components. First, you may specify the coordinate in absolute terms. For example:

with Schematic(filename = "rlc.svg"):
    Wire([(-75, -50), (75, -50), (75, 50), (-75, 50)])
    Wire([(0, -50), (0, 50)])
    Resistor(C=(-75, 0), name='R', orient='v')
    Capacitor(C=(0, 0), name='C', orient='v')
    Inductor((C=75, 0), name='L', orient='v|')

Notice that a wire is specified as a list of point, where each point is a tuple that contains an XY pair. The wire just connects the points with line segments. The location of the components is given by giving the location of a feature on the component. In this case it is the center (C) of the component that is specified. Again the location is an XY-pair.

This approach turns out to be rather cumbersome as it requires a lot of planning is a lot of work if you need to move things around. In that case you likely have to adjust a large number coordinates. Since schematics of any complexity are often adjusted repeatedly before they are correct and aesthetically appealing, this approach can lead to a lot of tedious work.

The second basic approach to placing component is to place them relative to each other. This approach is the one that is always used in practice. To do so, you would generally take advantage of the fact that components have attributes that contains useful coordinate locations on the component. For example:

r = Resistor(C=(0, 0), name='R', orient='v')

Now, r.C, r.N, r.NE, r.E, r.SE, r.S, r.SW, r.W, and r.NW contain the coordinates of the center, north, northeast, east, southeast, south, southwest, west, and northwest corners. In addition, r.p and r.n hold the coordinates of the positive and negative terminals. Finally, wires provide the b and e attributes, which contain the coordinates of their beginning and ending.

Once you place the first component, you then specify the location of the remaining components relative to one that has already been placed. To do so, you would give the location of one of the principle coordinates or the location of a terminal. For example:

r = Resistor(C=(0, 0), name='R', orient='v')
c = Capacitor(C=r.C, xoff=75, name='C', orient='v')
l = Inductor((C=c.C, xoff=75, name='L', orient='v|')
Wire([r.p, c.p, l.p], kind='-|-')
Wire([r.n, c.n, l.n], kind='-|-')

Notice that the center of r is placed at (0,0), then the center of c is place 75 units to the right of r, then the center of l is placed 75 units to the right of c. If c has to be moved for some reason then l will move with it. For example, only changing the line that instantiates the capacitor produces the following results:

c = Capacitor(C=r.C, off=(100, 25), name='C', orient='v')

The shift, shift_x, and shift_y utility functions are provided to shift the position of a coordinate pair. Examples:

.. code-block:: python

shift((x,y), dx, dy) –> (x+dx, y+dy) shift_x((x,y), dx) –> (x+dx, y) shift_y((x,y), dy) –> (x, y+dy)

To see how these might be useful, consider offsetting the wires so they sit a little further away from the components:

r = Resistor(C=(0, 0), name='R', orient='v')
c = Capacitor(C=r.C, xoff=75, name='C', orient='v')
l = Inductor((C=c.C, xoff=75, name='L', orient='v|')
Wire([r.p, shift_y(r.p, -12.5), shift_y(c.p, -12.5), c.p])
Wire([c.p, shift_y(c.p, -12.5), shift_y(l.p, -12.5), l.p])
Wire([r.n, shift_y(r.n, 12.5), shift_y(c.n, 12.5), c.n])
Wire([c.n, shift_y(c.n, 12.5), shift_y(l.n, 12.5), l.n])

You can also use with_x and with_y to replace the x or y portion of a coordinate pair. They take two arguments, the first is returned with the appropriate coordinate component replaced by the second. The second argument may be a simple number or it may be a coordinate pair, in which case the appropriate coordinate component is used to replace the corresponding component in the first argument:

with_x((x1,y1), x2) --> (x2, y1)
with_y((x1,y1), y2) --> (x1, y2)
with_x((x1,y1), (x2,y2)) --> (x2, y1)
with_y((x1,y1), (x2,y2)) --> (x1, y2)

Finally, the midpoint functions return the point midway between two points:

midpoint((x1,y1), (x2,y2) --> ((x1+x2)/2, (y1+y2)/2)
midpoint_x((x1,y1), (x2,y2) --> ((x1+x2)/2, y1)
midpoint_y((x1,y1), (x2,y2) --> (x1, (y1+y2)/2)

Arbitrary Drawing Features using SVGwrite

SVG_Schematic subclasses the Python svgwrite package Drawing class. So you can call any Drawing method from a schematic. In this case you must keep the schematic instance to access the methods:

with Schematic(filename = "hello.svg") as schematic:
    schematic.circle(
        center=(0,0), r=100, fill='none', stroke_width=1, stroke='black'
    )
    schematic.text(
        'Hello', insert=(0,0), font_family='sans', font_size=16, fill='black'
    )

One thing to note is that Schematic normally keeps track of the location and extent of the schematic objects and sizes the drawing accordingly. It will be unaware of anything added directly to the drawing though the svgwrite methods. As a result, these objects may fall partially or completely outside the bounds of the drawing. You can add padding when you first instantiate Schematic or you can use the svgwrite viewbox method to extend the bounds.

Latex

To include these schematics into Latex documents, you need to run Inkscape with the –export-latex command line option to generate the files that you can include in Latex. Here is a Makefile that you can use to keep all these files up to date:

DRAWINGS = \
    flash-adc \
    pipeline-adc \
    delta-sigma-adc

SVG_FILES=$(DRAWINGS:=.svg)
PDF_FILES=$(DRAWINGS:=.pdf)
PDFTEX_FILES=$(DRAWINGS:=.pdf_tex)

.PHONY: clean
.PRECIOUS: %.svg

%.svg: %.py
        python3 $<

%.pdf: %.svg
        inkscape -z -D --file=$< --export-pdf=$@ --export-latex

clean:
        rm -rf $(PDF_FILES) $(PDFTEX_FILES) __pycache__

To include the files into your Latex document, use:

\def\svgwidth{0.5\columnwidth}
\input{delta-sigma.pdf_tex}

Finally, to convert your Latex file to PDF, use:

pdflatex --shell-escape converters.tex

Other Image Formats

You can use Image Magick package to convert SVG files to other image formats. For example:

convert receiver.svg receiver.png

Resistor

Draw a resistor.

Resistor(name='Rs', value='50Ω')

Resistors take the following arguments: orient, name, value, nudge, C, N, NE, E, SE, S, SW, W, NW, p, n, off, xoff & yoff.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The p and n attributes contain the locations of the positive and negative terminals.

You may pass a wire directly under the resistor and the wire will be concealed by the resistor.

Capacitor

Draws a capacitor.

Capacitor(name='C1', value='1.2pF')

Capacitors take the following arguments: orient, name, value, nudge, C, N, NE, E, SE, S, SW, W, NW, p, n, off, xoff & yoff.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The p and n attributes contain the locations of the positive and negative terminals.

You may pass a wire directly under the capacitor and the wire will be concealed by the capacitor. The capacitor is polarized with reference end being terminal n.

Inductor

Draws an inductor.

Inductor(name='L1', value='1μH')

Inductors take the following arguments: orient, name, value, nudge, C, N, NE, E, SE, S, SW, W, NW, p, n, off, xoff & yoff.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The p and n attributes contain the locations of the positive and negative terminals.

You may pass a wire directly under the inductor and the wire will be concealed by the inductor.

Diode

Draws a diode.

Diode(name='D1')

Diodes take the following arguments: orient, name, value, nudge, C, N, NE, E, SE, S, SW, W, NW, p, n, off, xoff & yoff.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The a and c attributes contain the coordinates of the anode and cathode terminals.

You may pass a wire directly under the diode and the wire will be concealed by the diode.

BJT

Draws a bipolar transistor. Two kinds of BJT are available, npn and pnp.

MOS(kind='n', name='Qn')
MOS(kind='p', name='Qp')

BJTs take the following arguments: kind, orient, name, value, nudge, C, N, NE, E, SE, S, SW, W, NW, p, n, off, xoff & yoff. kind may be npn or pnp, or simply n or p.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The c, b and e attributes contain the coordinates of the collector, base and emitter terminals.

You may pass a wire directly under the transistor and the wire will be concealed by the transistor.

MOS

Draws a MOSFET. Three kinds of FET are available, nmos, pmos, and non-polarized.

MOS(kind='n', name='Mn')
MOS(kind='p', name='Mp')
MOS(kind='', name='M')

MOSFETs take the following arguments: kind, orient, name, value, nudge, C, N, NE, E, SE, S, SW, W, NW, p, n, off, xoff & yoff. kind may be nmos or pmos, or simply n or p. If an empty string is specified, the terminal locations are those of an nmos, but the arrow is not drawn.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The d, g and s attributes contain the coordinates of the drain, gate and source terminals.

You may pass a wire directly under the transistor and the wire will be concealed by the transistor.

Amplifier

Draws an amplifier. Four kinds of amplifier are available, single-ended, opamp, differential amplifier and comparator.

Amp(kind='se', name='As')
Amp(kind='oa', name='Ao')
Amp(kind='da', name='Ad')
Amp(kind='comp', name='Ac')

Amplifiers take the following arguments: kind, orient, name, value, C, N, NE, E, SE, S, SW, W, NW, p, n, off, xoff & yoff. kind may be se, oa, da or comp.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The pi, i, ni po, o, and no attributes contain the coordinates of the positive input, the input, the negative input, the positive output, the output, and the negative output terminals. All 6 pin attributes are always available, even if they do not seem appropriate for the kind of amplifier drawn.

You can reshape the amplifier using w and h to specify the width and height. The default values for each are 2, and you should not deviate too far from 2 or you will end up with an ugly amplifier.

You may pass a wire or wires directly under the amplifier and the wire will be concealed by the amplifier.

Gate

Draws a gate. Currently the only supported kind of gate is inv, an inverter.

Gate(kind='inv', name='U')

Gates take the following arguments: kind, orient, name, value, nudge, C, N, NE, E, SE, S, SW, W, NW, p, n, off, xoff & yoff. kind may be inv.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The i and o attributes contain the coordinates of the input and the output.

You may pass a wire or wires directly under the gate and the wire will be concealed by the gate.

Source

Draws a source. Eight kinds of source are available, empty, vdc, idc, sine, sum (summer), mult (multiplier), cv (controlled voltage) and ci (controlled current).

Source(kind='empty', name='Ve')
Source(kind='vdc', name='Vd')
Source(kind='idc', name='Id')
Source(kind='sine', name='Vs')
Source(kind='sum', name='S')
Source(kind='mult', name='M')
Source(kind='cv', name='Vc')
Source(kind='ci', name='Ic')

Sources take the following arguments: kind, orient, name, value, nudge, C, N, NE, E, SE, S, SW, W, NW, p, n, off, xoff & yoff. kind may be empty, vdc, idc, sine, sum, mult, cv or ci.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates, but unlike all other components, these are evenly distributed about the circle that envelopes the source. The p and n attributes contain the coordinates of the positive and negative pins. The pin attributes are always available, even if they do not seem appropriate for the kind of source drawn.

You may pass a wire or wires directly under the source and the wire will be concealed by the source.

Switch

Draws a switch. Two kinds of switch are available, spst (single-pole, single-throw) and spdt (single-pole, double-throw).

Switch(kind='spst', name='φ₁')
Switch(kind='spdt', name='φ₂')

Switches take the following arguments: kind, orient, name, value, dots, nudge, C, N, NE, E, SE, S, SW, W, NW, i, o, ot, ob, off, xoff & yoff. kind may be spst or spdt. The dots argument determines whether the poles of the switch should be denoted with large dots.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The i ot, o and ob attributes contain the coordinates of the input, the top output, the output, and the bottom output pins. The pin attributes are always available, even if they do not seem appropriate for the kind of switch drawn.

You may pass a wire or wires directly under the switch and the wire will be concealed by the switch.

Box

Draws a box.

Box(name='4 bit', value='Flash')
Box(name='𝘻⁻¹', w=1, h=1)

Boxes take the following arguments: orient, name, value, nudge, line_width, background, w, h, C, N, NE, E, SE, S, SW, W, NW, i, o, off, xoff & yoff. In addition, you may specify SVGwrite arguments, as shown in the example below.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The i and o attributes contain the coordinates of the input and output pins.

Boxes also support arbitrary svgwrite drawing parameters. This can be useful to draw the box with dashed lines:

Box(w=1, h=1, stroke_dasharray="4 2")

Ground

Draws a ground.

Ground()

Grounds take the following arguments: orient, name, value, nudge, C, N, NE, E, SE, S, SW, W, NW, t, off, xoff & yoff. Currently value is ignored.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The t attribute contains the coordinates of the ground’s terminal.

Pin

Draws a pin. Four kinds of pin are available, none, dot, in, and out.

Pin(kind='none', name='none', value='none value')
Pin(kind='dot', name='dot', value='dot value')
Pin(kind='in', name='in', yoff=50)
Pin(kind='out', name='out', yoff=50)

Here the pins are drawn with wires to give better context. The horizontal location of the pins is indicated with the vertical blue line.

Pins take the following arguments: kind, orient, name, value, nudge, w, h, color, C, N, NE, E, SE, S, SW, W, NW, t, off, xoff & yoff. Currently value is ignored for in and out pins.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The t attribute contains the coordinates of the pin.

It is important to remember that C represents the center of the tile used by the pin. Since the pin label will be on one side, C will not coincide with the apparent visual center of the pin and its label.

Pins of kind none do not draw a symbol. Rather they are used to place labels at a particular point. dot pins place a small filled circle that is usually used to represent a solder dot (though you can change the color to the background color, generally ‘white’, and place it between two crossing wires to create a visual gap in the lower wire). Pins of type in and out render with a hollow circle that is offset slightly a wire terminates on one side. These two pin types ignore the value argument.

By default the width and height of the pin are 1, meaning that a unit sized tile (50×50) is used. This is significant if the label is at the edge of the schematic. If the labels extend beyond the tile, they may extend beyond the computed viewbox for the schematic. You can fix this by specifying a larger width or height.

Dot

Draw a solder dot (a small filled circle) or a wire gap (a small filled circle with the color of the background that is placed between two crossing wires). Dot is just an alias for Pin, except that the default kind is ‘dot’.

Dot()

Label

Place a label. Five kinds of label are available, plain, arrow, arrow|, slash, and dot.

Label(kind='plain', name='plain', loc='se')
Label(kind='arrow', name='arrow', loc='se')
Label(kind='arrow|', name='arrow|', loc='se')
Label(kind='slash', name='slash', loc='se')
Label(kind='dot', name='dot', loc='se')

Here the labels are drawn with wires to give better context. The horizontal location of the labels is indicated with the vertical blue line.

Labels take the following arguments: kind, orient, name, value, loc, w, h, color, nudge, C, N, NE, E, SE, S, SW, W, NW, off, xoff & yoff. Currently value is ignored.

The C, N, NE, E, SE, S, SW, W, NW attributes contain the locations of the principle coordinates. The t attribute contains the coordinates of the label.

The kind may be ‘plain’, ‘arrow’, ‘arrow|’, ‘slash’ or ‘dot’. If ‘plain’ is specified, no symbol is added, only the name is displayed. If ‘arrow’ is specified, an arrow is added and the centered on the specified location. If ‘arrow|’ is specified, the arrow terminates on the specified location. If ‘slash’ is specified, a small slash is added through the center. It is generally used with buses to indicate the bus width. Finally, ‘dot’ adds a solder dot.

By default the width and height of the label are 1, meaning that a unit sized tile (50×50) is used. This is significant if the label is at the edge of the schematic. If the labels extend beyond the tile, they may extend beyond the computed viewbox for the schematic. You can fix this by specifying a larger width or height.

It is important to remember that C represents the center of the tile used by the label. Since the label will be on one side, C will not coincide with the apparent visual center of the label.

Exceptions

In the rare cases where SVG_Schematic it raises an Inform Error. SVG_Schematic is a wrapper around svgwrite. It is not clear what exceptions it will raise, but at a minimum it would raise OSError it is is unable to open or close the SVG file. Thus you should catch these two exceptions. See noninverting amplifier to see how this is done.

Non Inverting Amplifier

Here is an example of a typical schematic with exception handling.

#!/usr/bin/env python3

from svg_schematic import (
    Schematic, Amp, Dot, Ground, Label, Pin, Resistor, Source, Wire
)
from inform import Error, error, os_error

try:
    with Schematic(filename = "noninverting.svg"):

        vin = Source(kind='sine')
        Label(C=vin.p, name='Vin', loc='n')
        Ground(C=vin.n)
        amp = Amp(pi=vin.p, xoff=100, kind='oa')
        Label(C=amp.ni, xoff=-25, name='Ve', loc='n')
        Wire([vin.p, amp.pi])
        out = Pin(C=amp.o, xoff=50, name='out', w=2)
        Wire([amp.o, out.C])
        oj = Dot(C=amp.o, xoff=25)
        r1 = Resistor(p=amp.ni, off=(-25, 50), name='R1', orient='v')
        Wire([r1.N, amp.ni], kind='|-')
        r2 = Resistor(C=amp.C, yoff=75, name='R2')
        Wire([r1.p, r2.W], kind='|-')
        Wire([oj.C, r2.E], kind='|-')
        fj = Dot(C=r2.W, xoff=-25)
        Ground(C=r1.n)

except Error as e:
    e.report()
except OSError as e:
    error(os_error(e))

Passive Low Pass Filter

This example uses QuantiPhy to compute the values for the components in a low pass filter and then constructs the schematic using those values.

"""
Draw a 5th Order Low Pass Passive Filer with Maximally Flat Envelope Delay

Use the following parameters:
    Fo = 1MHz   -- 3dB corner frequency
    Rref = 50Ω  -- termination impedance

Design equations:
    Omega0 = 2*π*Fo
    Lscale = Rref/Omega0
    Cscale = 1/(Rref*Omega0)

    Rs = 1.0000 * Rref   "Ω"
    C1 = 0.2715 * Cscale "F"
    L2 = 0.6541 * Lscale "H"
    C3 = 0.8892 * Cscale "F"
    L4 = 1.1034 * Lscale "H"
    C5 = 2.2873 * Cscale "F"
"""

from svg_schematic import (
    Schematic, Capacitor, Ground, Inductor, Resistor, Pin, Source, Wire
)
from inform import Error, error, os_error
from quantiphy import Quantity
from math import pi

Quantity.set_prefs(map_sf=Quantity.map_sf_to_greek, prec=2)
globals().update(
    Quantity.extract(__doc__, predefined={'π': pi})
)

try:
    with Schematic(filename = 'mfed.svg', background = 'none'):

        vin = Source(name='Vin', value='1 V', kind='sine')
        Ground(C=vin.n)
        rs = Resistor(name='Rs', value=Rref, n=vin.p, xoff=25)
        Wire([vin.p, rs.n])
        c1 = Capacitor(name='C1', value=C1, p=rs.p, xoff=25)
        Ground(C=c1.n)
        l2 = Inductor(name='L2', value=L2, n=c1.p, xoff=25)
        Wire([rs.p, l2.n])
        c3 = Capacitor(name='C3', value=C3, p=l2.p, xoff=25)
        Ground(C=c3.n)
        l4 = Inductor(name='L4', value=L4, n=c3.p, xoff=25)
        Wire([l2.p, l4.n])
        c5 = Capacitor(name='C5', value=C5, p=l4.p, xoff=25)
        Ground(C=c5.n)
        rl = Resistor(name='Rl', value=Rref, p=c5.p, xoff=100, orient='v')
        Ground(C=rl.n)
        out = Pin(name='out', C=rl.p, xoff=50, w=2)
        Wire([l4.p, out.t])

except Error as e:
    e.report()
except OSError as e:
    error(os_error(e))