Dosya:Transmission line pulse reflections.gif
Sayfa içeriği diğer dillerde desteklenmemektedir.
Görünüm
Vikipedi, özgür ansiklopedi
Bu önizlemenin boyutu: 800 × 293 piksel. Diğer çözünürlükler: 320 × 117 piksel | 900 × 330 piksel.
Tam çözünürlük ((900 × 330 piksel, dosya boyutu: 1,87 MB, MIME tipi: image/gif), döngüye girdi, 240 kare, 12 sn)
Bu dosya Wikimedia Commons'ta bulunmaktadır. Dosyanın açıklaması aşağıda gösterilmiştir. Commons, serbest/özgür telifli medya dosyalarının bulundurulduğu depodur. Siz de yardım edebilirsiniz. |
Özet
AçıklamaTransmission line pulse reflections.gif |
English: Transmission lines terminated by an open circuit (top) and a short circuit (bottom). A pulse reflects off the termination. Black dots represent electrons, and arrows show the electric field. |
Tarih | |
Kaynak | Yükleyenin kendi çalışması |
Yazar | Sbyrnes321 |
Lisanslama
Ben, bu işin telif sahibi, burada işi aşağıdaki lisans altında yayımlıyorum:
Bu dosya Creative Commons Evrensel Kamu Malı İthafı altındadır. | |
Bu çalışmayı oluşturan kişi bu senet ile eser hakkında tüm dünya çapında telif hakkı yasaları kapsamında, yasalar tarafından izin verilen ölçülerde ve diğer benzer tüm haklarından feragat etmiş ve kamu malı olarak nitelendirmiştir. Siz bu çalışmayı ve eseri hiç bir izin almadan ticari amaçlar da dahil olmak üzere kopyalayabilir, değiştirebilir ve serbestçe dağıtabilirsiniz.
http://creativecommons.org/publicdomain/zero/1.0/deed.enCC0Creative Commons Zero, Public Domain Dedicationfalsefalse |
Source code
"""
(C) Steven Byrnes, 2014-2016. This code is released under the MIT license
http://opensource.org/licenses/MIT
This code runs in Python 2.7 or 3.3. It requires imagemagick to be installed;
that's how it assembles images into animated GIFs.
"""
# Use Python 3 style division: a/b is real division, a//b is integer division
from __future__ import division
import subprocess, os
directory_now = os.path.dirname(os.path.realpath(__file__))
import pygame as pg
from numpy import linspace
from math import erf, exp
frames_in_anim = 240
animation_loop_seconds = 12 #time in seconds for animation to loop one cycle
bgcolor = (255,255,255) #background is white
ecolor = (0,0,0) #electrons are black
wire_color = (200,200,200) # wire color is light gray
split_line_color = (0,0,0) #line down the middle is black
arrow_color = (140,0,0)
# pygame draws pixel-art, not smoothed. Therefore I am drawing it
# bigger, then smoothly shrinking it down
img_height = 330
img_width = 900
final_height = 110
final_width = 300
# ~23 megapixel limit for wikipedia animated gifs
assert final_height * final_width * frames_in_anim < 22e6
# transmission line wire length and thickness, and y-coordinate of the top of
# each wire
tl_length = int(img_width * .9)
tl_thickness = 27
tl_open_top_y = 30
tl_open_bot_y = tl_open_top_y + 69
tl_short_top_y = 204
tl_short_bot_y = tl_short_top_y + 69
tl_open_center_y = int((tl_open_top_y + tl_open_bot_y + tl_thickness) / 2)
tl_short_center_y = int((tl_short_top_y + tl_short_bot_y + tl_thickness) / 2)
wavelength = 1.1 * tl_length
e_radius = 4
# dimensions of triangular arrow head (this is for the longest arrows; it's
# scaled down when the arrow is too small)
arrowhead_base = 9
arrowhead_height = 15
# width of the arrow line
arrow_width = 6
# number of electrons spread out over the transmission line (top plus bottom)
num_electrons = 130
# max_e_displacement is defined here as a multiple of the total electron path length
# (roughly twice the width of the image, because we're adding top + bottom)
max_e_displacement = 0.0194
num_arrows = 30
max_arrow_halflength = 24
def tup_round(tup):
"""round each element of a tuple to nearest integer"""
return tuple(int(round(x)) for x in tup)
def draw_arrow(surf, x, tail_y, head_y):
"""
draw a vertical arrow. Coordinates do not need to be integers
"""
# calculate dimensions of the triangle; it's scaled down for short arrows
if abs(head_y - tail_y) >= 1.5 * arrowhead_height:
h = arrowhead_height
b = arrowhead_base
else:
h = abs(head_y - tail_y) / 1.5
b = arrowhead_base * h / arrowhead_height
if tail_y < head_y:
# downward arrow
triangle = [tup_round((x, head_y)),
tup_round((x - b, head_y - h)),
tup_round((x + b, head_y - h))]
triangle_middle_y = head_y - h/2
else:
# upward arrow
triangle = [tup_round((x, head_y)),
tup_round((x - b, head_y + h)),
tup_round((x + b, head_y + h))]
triangle_middle_y = head_y + h/2
pg.draw.line(surf, arrow_color, tup_round((x, tail_y)),
tup_round((x, triangle_middle_y)), arrow_width)
pg.draw.polygon(surf, arrow_color, triangle, 0)
def pulse(c, t, open_or_short):
"""
c is a coordinate, c=0 is the left side of the image, c=1 is the terminal
t is time, with t=0 at the beginning of the animation, t=1 at the end
This calculates two things:
* Displacement of an electron in the top wire relative to its equilibrium
position (i.e., integral of I(x,t') from t'=-infty to t'=t), in
arbitrary units.
* Charge on the top wire at that location, in arbitrary units.
"""
assert c <= 1
# We imagine that c>1 is a "mirror-world" beyond the terminal, which will
# not be actually drawn. Then we can add up a leftward-traveling pulse and
# a rightward-traveling pulse, using the superposition principle
pulse_speed = 3
pulse_width = 0.2
if open_or_short == 'open':
pulses = [{'center': 1 + pulse_speed * (t - 0.5), 'sign': +1},
{'center': 1 - pulse_speed * (t - 0.5), 'sign': +1}]
else:
pulses = [{'center': 1 + pulse_speed * (t - 0.5), 'sign': +1},
{'center': 1 - pulse_speed * (t - 0.5), 'sign': -1}]
displacement = 0
charge = 0
for pulse in pulses:
center, sign = pulse['center'], pulse['sign']
displacement += erf((c - center) / pulse_width) * sign
charge += exp(-(c - center)**2 / pulse_width**2) * sign
return {'displacement': displacement, 'charge': charge/2}
def e_path_open(param, time):
"""
"param" is an abstract coordinate that goes from 0 to 1 as the electron
position goes right across the top wire then left across the bottom wire.
"time" goes from 0 to 1 over the course of the animation.
This returns a dictionary: 'pos' is (x,y), the
coordinates of the corresponding point on the electron
dot path; 'displacement' is the displacement of an electron at this point
relative to its equilibrium position (between -1 and -1); and 'charge' is
the net charge at this point (between -1 and +1)
This is for the open-circuit line.
"""
# d is a vertical offset between the electrons and the wires
d = e_radius + 2
# pad is how far to extend the transmission line beyond the image borders
# (since those electrons may enter the image a bit)
pad = 120
path_length = 2 * (tl_length + pad)
howfar = param * path_length
#go right along top transmission line
if howfar < tl_length + pad:
x = howfar - pad
y = tl_open_top_y + tl_thickness - d
temp = pulse(x / tl_length, time, 'open')
displacement = temp['displacement']
charge = temp['charge']
return {'pos':(x,y), 'displacement': displacement, 'charge': charge}
#go left along bottom transmission line
x = path_length - howfar - pad
y = tl_open_bot_y + d
temp = pulse(x / tl_length, time, 'open')
displacement = temp['displacement']
charge = -temp['charge']
return {'pos':(x,y), 'displacement': displacement, 'charge': charge}
def e_path_short(param, time):
"""Same as e_path_open(...) above, but for the short-circuit line."""
# d is a vertical offset between the electrons and the wires
d = e_radius + 2
# pad is how far to extend the transmission line beyond the image borders
# (since those electrons may enter the image a bit)
pad = 120
path_length = (2 * (tl_length + pad) + 4*d
+ (tl_short_bot_y - tl_short_top_y - tl_thickness))
howfar = param * path_length
#at the beginning, go right along top wire
if howfar < tl_length + pad:
x = howfar - pad
y = tl_short_top_y + tl_thickness - d
temp = pulse(x / tl_length, time, 'short')
displacement = temp['displacement']
charge = temp['charge']
return {'pos':(x,y), 'displacement': displacement, 'charge': charge}
#at the end, go left along bottom wire
if (path_length - howfar) < tl_length + pad:
x = path_length - howfar - pad
y = tl_short_bot_y + d
temp = pulse(x / tl_length, time, 'short')
displacement = temp['displacement']
charge = -temp['charge']
return {'pos':(x,y), 'displacement': displacement, 'charge': charge}
#in the middle...
temp = pulse(1, time, 'short')
charge = temp['charge']
assert abs(charge) < 1e-9
displacement = temp['displacement']
#top part of short...
if tl_length + pad < howfar < tl_length + pad + d:
x = howfar - pad
y = tl_short_top_y + tl_thickness - d
#bottom part of short...
elif tl_length + pad < (path_length - howfar) < tl_length + pad + d:
x = path_length - howfar - pad
y = tl_short_bot_y + d
#vertical part of short...
else:
x = tl_length + d
y = (tl_short_top_y + tl_thickness - d) + ((howfar-pad) - (tl_length + d))
return {'pos': (x,y), 'displacement': displacement, 'charge': charge}
def e_path(param, time, which):
return e_path_open(param, time) if which == 'open' else e_path_short(param, time)
def main():
#Make and save a drawing for each frame
filename_list = [os.path.join(directory_now, 'temp' + str(n) + '.png')
for n in range(frames_in_anim)]
for frame in range(frames_in_anim):
time = frame / frames_in_anim
#initialize surface
surf = pg.Surface((img_width,img_height))
surf.fill(bgcolor);
#draw transmission line
pg.draw.rect(surf, wire_color, [0, tl_open_top_y, tl_length, tl_thickness])
pg.draw.rect(surf, wire_color, [0, tl_open_bot_y, tl_length, tl_thickness])
pg.draw.rect(surf, wire_color, [0, tl_short_top_y, tl_length, tl_thickness])
pg.draw.rect(surf, wire_color, [0, tl_short_bot_y, tl_length, tl_thickness])
pg.draw.rect(surf, wire_color, [tl_length,
tl_short_top_y,
tl_thickness,
tl_short_bot_y - tl_short_top_y + tl_thickness])
#draw line down the middle
pg.draw.line(surf,split_line_color, (0,img_height//2),
(img_width,img_height//2), 12)
#draw electrons. Remember, "param" is an abstract coordinate that goes
#from 0 to 1 as the electron position goes right across the top wire
#then left across the bottom wire
equilibrium_params = linspace(0, 1, num=num_electrons)
for which in ['open', 'short']:
for eq_param in equilibrium_params:
temp = e_path(eq_param, time, which)
param_now = eq_param + max_e_displacement * temp['displacement']
xy_now = e_path(param_now, time, which)['pos']
pg.draw.circle(surf, ecolor, tup_round(xy_now), e_radius)
#draw arrows
arrow_params = linspace(0, 0.49, num=num_arrows)
for which in ['open', 'short']:
center_y = tl_open_center_y if which == 'open' else tl_short_center_y
for i in range(len(arrow_params)):
a = arrow_params[i]
arrow_x = e_path(a, time, which)['pos'][0]
charge = e_path(a, time, which)['charge']
head_y = center_y + max_arrow_halflength * charge
tail_y = center_y - max_arrow_halflength * charge
draw_arrow(surf, arrow_x, tail_y, head_y)
#shrink the surface to its final size, and save it
shrunk_surface = pg.transform.smoothscale(surf, (final_width, final_height))
pg.image.save(shrunk_surface, filename_list[frame])
seconds_per_frame = animation_loop_seconds / frames_in_anim
frame_delay = str(int(seconds_per_frame * 100))
# Use the "convert" command (part of ImageMagick) to build the animation
command_list = ['convert', '-delay', frame_delay, '-loop', '0'] + filename_list + ['anim.gif']
subprocess.call(command_list, cwd=directory_now)
# Earlier, we saved an image file for each frame of the animation. Now
# that the animation is assembled, we can (optionally) delete those files
if True:
for filename in filename_list:
os.remove(filename)
main()
Bu dosyada gösterilen öğeler
betimlenen
Vikiveri ögesi olmayan bir değer
15 Kasım 2014
image/gif
Dosya geçmişi
Dosyanın herhangi bir zamandaki hâli için ilgili tarih/saat kısmına tıklayın.
Tarih/Saat | Küçük resim | Boyutlar | Kullanıcı | Yorum | |
---|---|---|---|---|---|
güncel | 19.05, 18 Mart 2024 | 900 × 330 (1,87 MB) | MrAureliusR | Larger size, tweaks made to diagram to make it easier to understand, added labels | |
02.04, 29 Mayıs 2016 | 300 × 110 (442 KB) | Sbyrnes321 | all arrows are red, to reduce image complexity | ||
14.47, 15 Kasım 2014 | 300 × 110 (605 KB) | Sbyrnes321 | User created page with UploadWizard |
Dosya kullanımı
Bu görüntü dosyasına bağlantısı olan sayfalar:
Küresel dosya kullanımı
Aşağıdaki diğer vikiler bu dosyayı kullanır:
- en.wikipedia.org üzerinde kullanımı
"https://tr.wikipedia.org/wiki/Dosya:Transmission_line_pulse_reflections.gif" sayfasından alınmıştır