# A small black component with "680" or "089" inscribed on it

#### Lawrence H

Joined May 6, 2019
98
Hey!

I got my hands on some USB LED lights. I opened one up to have a look, and there is a small component, about 5 mm in length, and 2 mm wide. There is one of them per LED light, so 12 all together.

What component is this?

Thanks!

#### k1ng 1337

Joined Sep 11, 2020
911
A picture paints a thousand words

#### Ya’akov

Joined Jan 27, 2019
8,974
They are current limiting resistors for the LEDs to make keep the LEDs from turning to smoke when the power is connected. The value will depend on the applied voltage and the current the designer wants each LED to use.

Many LED lights push the LEDs at currents that shorten their lives considerably but reduce the number of LEDs needed to produce the amount of light desired.

#### Lawrence H

Joined May 6, 2019
98

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#### djsfantasi

Joined Apr 11, 2010
9,151
Here you go
The comment describing it as a resistor just went up to 95% correct.

#### MrChips

Joined Oct 2, 2009
30,497
680 on a resistor indicates that the resistance is 68Ω.
681 would be 680Ω.

#### Lawrence H

Joined May 6, 2019
98
They are current limiting resistors for the LEDs to make keep the LEDs from turning to smoke when the power is connected. The value will depend on the applied voltage and the current the designer wants each LED to use.

Many LED lights push the LEDs at currents that shorten their lives considerably but reduce the number of LEDs needed to produce the amount of light desired.
What does the number stand die do you know?

I am playing around with electronics, that sentence sounds frighteming but I am being careful. I burned one of the LEDs with a solder since it wouldn't come off. I wonder could there be any use for these resistors?

Also, this light is the same on both sides, so am I safe to assume that the actual circuit is in the middle if these two light circuits? I don't see any connecting wires. Also I'm not sure I am using the correct terminology since I'm not familiar with electronics in English.

#### Lawrence H

Joined May 6, 2019
98
680 on a resistor indicates that the resistance is 68Ω.
681 would be 680Ω.
That's interesting. Thanks for this. What would 8611 be?

#### MrChips

Joined Oct 2, 2009
30,497
8611 on any component is more likely to be the date code, i.e. the 11th week of 1986.

It is not likely to be a resistor value because 8610Ω is not a standard resistance value being manufactured.
8661 would be 8660Ω which is a standard value in the E96 series.

#### Lawrence H

Joined May 6, 2019
98
8611 on any component is more likely to be the date code, i.e. the 11th week of 1986.

It is not likely to be a resistor value because 8610Ω is not a standard resistance value being manufactured.
8661 would be 8660Ω which is a standard value in the E96 series.
Gotcha. Thanks everybody! I now know what I have in my hands.

#### Ya’akov

Joined Jan 27, 2019
8,974
What does the number stand die do you know?

I am playing around with electronics, that sentence sounds frighteming but I am being careful. I burned one of the LEDs with a solder since it wouldn't come off. I wonder could there be any use for these resistors?

Also, this light is the same on both sides, so am I safe to assume that the actual circuit is in the middle if these two light circuits? I don't see any connecting wires. Also I'm not sure I am using the correct terminology since I'm not familiar with electronics in English.
Resistor codes on SMD (Surface Mount Device) parts is not hard to read. Older through-hole resistors used colored stripes to indicate the value, but the tiny SMD parts don't have room for that, so they use numbers.

This calculator can do the work for you, but the scheme is worth learning so you don't need it. This graphic explains it by example, the article it came from is worth a read, it covers a lot you should know.

PCBs (Printed Circuit Boards) can have many layers. They are made like a sandwich of the board material (often a particular fiberglass) and copper layers. The copper forms the traces, and there can be traces inside the PCB where you can't see them.

However, this case, it is probably just a 2-layer board with copper traces on the front any back. Connections are made with vias which are plated through holes that connect one copper layer to another like little tube shaped wires passing through the board. You can spot them if you look for them.

#### k1ng 1337

Joined Sep 11, 2020
911
Take a photo of every angle so all parts can be seen. Look for serial numbers and google any text you can find. If it's not junk you could pull up a circuit diagram and even a manual both for individual components and the entire device. Very helpful for me.

#### MisterBill2

Joined Jan 23, 2018
17,833

#### MisterBill2

Joined Jan 23, 2018
17,833
The 3-character resistor number code =68 x 10**0 =68 x1=68 ohms. So now you know.