Old School and stuck on component ID

Dave Jackson

May 5, 2016
5
Hi all. As the title suggests I am pretty old school and am struggling to ID many of the surface mount components used today. I am trying to ID the part in the picture with 201 stamped on top. It is wired in parallel to the LED (which I think is 1 watt as it draws 400ma @ 2.4 volts)

I am working on an LED light fixture made up of 135 LED's made up of three banks of 45 LED's wired in series and supplied by a 100-140v LED driver for each bank of 45 LED's. Each LED is paralleed with this 201 component. I have two dead LED"s and one also has this component (201) which has fried and broken apart.

Could someone please assist me to ID this part and a suitable replacement for it?

Last edited by a moderator:

davenn

Moderator
Sep 5, 2009
14,213
hi there
welcome to EP

the 201 is a 200 Ohm surface mount resistor

for your info ... the 3 digit scheme works as this .... first 2 digits are values
and the 3rd digit is the number of following zeros for a total Ohms, so 20 and 1 zero = 200 Ohms

203 = 20 + 3 zeros = 20000 Ohms = 20 kΩ
154 = 15 + 4 zeros = 150000 Ohms = 150 kΩ

Dave

Last edited:

Dave Jackson

May 5, 2016
5
hi there
welcome to EP

the 201 is a 200 Ohm surface mount resistor

for your info ... the 3 digit scheme works as this .... first 2 digits are values
and the 3rd digit is the number of following zeros for a total Ohms, so 20 and 1 zero = 200 Ohms

203 = 20 + 3 zeros = 20000 Ohms = 20 kΩ
154 = 15 + 4 zeros = 150000 Ohms = 150 kΩ

Dave

Hi Dave and thank you!
D'oh, a resistor eh I was thinking a diode or zener by the package, just goes to show I should trust my test gear which said 198 ohm lol

Is there a resource where I can look up these things? I found one site that said it was a zener but the picture showed a 3 leg device so was wrong.

Thanks again!
Dave

davenn

Moderator
Sep 5, 2009
14,213
Is there a resource where I can look up these things?

just google surface mount (SMD) resistors, you will likely get 100's of links to useful info

cheers
Dave

dorke

Jun 20, 2015
2,342
Old school?
Look at it as the same numerical, no-color code for 3 and 4 digit codes.
There are some more codes , here is a nice site including a calculator and video.
Another issue is the SMD resistors sizes/wattage.

In general ,for ceramic caps SMD is a head-hack,the parts are not marked!!!
For SMD transistors etc. it is a jungle...a machete will not always help to clear

Dave Jackson

May 5, 2016
5
Old school in the respect my electronics experiance was from hobbying in my teens, am mid 50s now and getting back to it as a hobby after a career as an electrician specilizing in high end commercial appliances. Since the advent of SMD's the physical look of the components has changed a lot and many types seem to look much the same, not to mention being able to see them at my age lol. Getting back into it seems to be a bit of a welcome to the jungle situation!
I guess we are not meant to repair anything anyway these days but I just can't help myself and have to try
Thanks for the link and help!
Cheers
Dave

cjdelphi

Oct 26, 2011
1,166
400ma per LED? That's with or without current limiting?

Over 100watts of light? So each led has a 200ohm smd resistor? Which brings the current right down no where near 400ma

I'm confused by the setup

cjdelphi

Oct 26, 2011
1,166
Maybe the fact it use 1watt leds and not something lower rated got me confused

Dave Jackson

May 5, 2016
5
400ma per LED? That's with or without current limiting?

Over 100watts of light? So each led has a 200ohm smd resistor? Which brings the current right down no where near 400ma

I'm confused by the setup
To be honest I am a bit confused by the setup myself and suspect there is some poor design in the fixture, it claims 300 watt total from 135 leds which doesn't match up with any wattage LED I can find on the market. I have read that a 3 watt led will replace a 1 watt one and figuring the total wattage suggests 1.5 watt that doesn't seem to exist I am hedging my bets and going with a 3 w replacment. Its also weird that it has two drivers for each bank in parallel... a truely weird design... it even has six cooling fans... interestingly the LEDs that failed are down the centreline between the fans so maybe there is a hot spot and they overheated. With all the leds in series and each having a paralleled 200 ohm resistor that looks to be about half watt, when the diode died its tried to draw all the load of the other leds through the smd resistor for the dead led, the resistor didn't stand a chance.

Herschel Peeler

Feb 21, 2016
401
hi there
welcome to EP

the 201 is a 200 Ohm surface mount resistor

for your info ... the 3 digit scheme works as this .... first 2 digits are values
and the 3rd digit is the number of following zeros for a total Ohms, so 20 and 1 zero = 200 Ohms

203 = 20 + 3 zeros = 20000 Ohms = 20 kΩ
154 = 15 + 4 zeros = 150000 Ohms = 150 kΩ

Dave

A part number off the LED might be helpful in determining a replacement.

Dave Jackson

May 5, 2016
5
A part number off the LED might be helpful in determining a replacement.
Hi
Unfortuneately the diode is completely blank with no ID what so ever, the only mark on it is the stamp to show the anode.
Cheers
Dave

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