While wiring up the LED stress tester, I realized I should abuse a string of amber LEDs along with the three red strings. Herewith, four amber LEDs from the top of their bag, with LED 5 = LED 1 retested:
Apart from being an outlier, that red trace seems much prettier than the others, doesn’t it?
The data file:
# LED Curve Tracer # Ed Nisley - KE4ZNU - December 2012 # VCC at LED: 4872 mV # Bandgap reference voltage: 1039 mV # Insert LED, press button 1 to start... # INOM ILED VccLED VD VLED VG VS VGS VDS <--- LED 1 0 0 4872 3668 1203 0 0 0 3668 10 10087 4872 2951 1920 2079 105 1973 2845 20 19716 4872 2898 1973 2257 207 2050 2691 30 30262 4872 2864 2007 2416 317 2099 2546 40 39891 4872 2840 2031 2551 418 2132 2421 50 49520 4872 2821 2050 2686 519 2166 2301 60 59607 4872 2806 2065 2811 625 2185 2180 70 69694 4872 2792 2079 2927 731 2195 2060 80 79782 4872 2777 2094 3061 837 2224 1940 90 90328 4872 2768 2103 3206 948 2257 1819 100 99957 4867 2763 2103 3307 1049 2257 1713 # Insert LED, press button 1 to start... # INOM ILED VccLED VD VLED VG VS VGS VDS <--- LED 2 0 0 4872 3991 881 0 0 0 3991 10 9628 4872 2946 1925 2084 101 1983 2845 20 20174 4872 2888 1983 2257 211 2046 2676 30 30262 4872 2850 2022 2416 317 2099 2532 40 39891 4872 2826 2046 2551 418 2132 2407 50 49978 4872 2802 2070 2681 524 2156 2277 60 60066 4872 2782 2089 2811 630 2180 2152 70 69694 4872 2768 2103 2936 731 2205 2036 80 79782 4872 2753 2118 3076 837 2238 1916 90 89869 4872 2744 2127 3177 943 2233 1800 100 99957 4872 2739 2132 3297 1049 2248 1689 # Insert LED, press button 1 to start... # INOM ILED VccLED VD VLED VG VS VGS VDS <--- LED 3 0 0 4872 3788 1083 0 0 0 3788 10 9628 4872 2941 1930 2084 101 1983 2840 20 19716 4872 2888 1983 2262 207 2055 2681 30 29803 4872 2850 2022 2412 312 2099 2537 40 39891 4872 2826 2046 2551 418 2132 2407 50 49978 4872 2806 2065 2681 524 2156 2282 60 60066 4872 2787 2084 2811 630 2180 2156 70 70153 4872 2777 2094 2960 736 2224 2041 80 80240 4872 2768 2103 3061 842 2219 1925 90 90328 4872 2753 2118 3182 948 2233 1805 100 99957 4867 2753 2113 3302 1049 2253 1704 # Insert LED, press button 1 to start... # INOM ILED VccLED VD VLED VG VS VGS VDS <--- LED 4 0 0 4872 3899 972 0 0 0 3899 10 9628 4872 2936 1935 2084 101 1983 2835 20 19716 4872 2888 1983 2262 207 2055 2681 30 29803 4872 2854 2017 2412 312 2099 2542 40 39891 4872 2835 2036 2551 418 2132 2416 50 49978 4872 2816 2055 2681 524 2156 2291 60 60066 4872 2797 2075 2816 630 2185 2166 70 70153 4872 2787 2084 2927 736 2190 2050 80 80240 4872 2773 2099 3061 842 2219 1930 90 90328 4867 2768 2099 3196 948 2248 1819 100 99957 4872 2758 2113 3331 1049 2282 1709 # Insert LED, press button 1 to start... # INOM ILED VccLED VD VLED VG VS VGS VDS <--- LED 5 0 0 4872 3841 1030 0 0 0 3841 10 10087 4872 2951 1920 2079 105 1973 2845 20 20174 4872 2907 1964 2257 211 2046 2696 30 30262 4872 2869 2002 2412 317 2094 2551 40 39891 4872 2845 2026 2551 418 2132 2426 50 50437 4872 2826 2046 2686 529 2156 2296 60 60066 4872 2806 2065 2821 630 2190 2176 70 69694 4872 2797 2075 2941 731 2209 2065 80 80240 4872 2782 2089 3076 842 2233 1940 90 89869 4872 2773 2099 3177 943 2233 1829 100 99957 4872 2763 2108 3321 1049 2272 1713 # Insert LED, press button 1 to start...
The Bash / Gnuplot routine that produced the graph has a few tweaks:
#!/bin/sh
numLEDs=4
#-- overhead
export GDFONTPATH="/usr/share/fonts/truetype/"
base="${1%.*}"
echo Base name: ${base}
ofile=${base}.png
echo Input file: $1
echo Output file: ${ofile}
#-- do it
gnuplot << EOF
#set term x11
set term png font "arialbd.ttf" 18 size 950,600
set output "${ofile}"
set title "${base}"
set key noautotitles
unset mouse
set bmargin 4
set grid xtics ytics
set xlabel "Forward Voltage - V"
set format x "%6.3f"
set xrange [1.8:2.2]
#set xtics 0,5
set mxtics 2
#set logscale y
#set ytics nomirror autofreq
set ylabel "Current - mA"
set format y "%4.0f"
set yrange [0:120]
set mytics 2
#set y2label "right side variable"
#set y2tics nomirror autofreq 2
#set format y2 "%3.0f"
#set y2range [0:200]
#set y2tics 32
#set rmargin 9
set datafile separator "\t"
set label 1 "LED 1 = LED $((numLEDs + 1))" at 2.100,110 right font "arialbd,18"
set arrow from 2.100,110 to 2.105,103 lt 1 lw 2 lc 0
plot \
"$1" index 0:$((numLEDs - 1)) using (\$5/1000):(\$2/1000):(column(-2)) with linespoints lw 2 lc variable,\
"$1" index $numLEDs using (\$5/1000):(\$2/1000) with linespoints lw 2 lc 0
EOF
The Smell of Molten Projects in the Morning 