Never seen this before: 'L'

Thread Starter

canillas

Joined May 6, 2023
6
Anyone has any idea what could it be? It is similar to a resistance but not sure with that letter 'L'
It meassures about 220 Ohms like an 221 SMD resistor, but I not sure what it is.
Could it be a filter ? There are four of this in serial and three measures the same, about 220 Ohms but one of them meassures 23 megaohms, so I think it could be opened.
 

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Papabravo

Joined Feb 24, 2006
21,297
'L' is the standard symbol for an inductor. There would usually be some wire wound around a form or bobbin. The pictures do no clearly show what you are talking about.
 

Thread Starter

canillas

Joined May 6, 2023
6
It is usual to use 'L' letter at shematics or in PCBs, but never seen on a SMD before. For that reason I am not sure what it is.
 

Irving

Joined Jan 30, 2016
4,043
A 2-pin SMD device wth a single letter marking could be a fuse, L being 1Amp. However, in a group like that, a fuse makes little sense, so my guess is they are inductors used as noise filters on signal lines (power lines would be much lower resistance). Quite often, under fault conditions, these are known to act as fuses.
 

Thread Starter

canillas

Joined May 6, 2023
6
If are inductors it is suposed that having the same letter might be the same value? How can I guess that without the schematic diagram?
 

MrChips

Joined Oct 2, 2009
31,057
I guess based on its size, matches 1206 that are only about 1/4w. But I am not sure the odds of having 6 resistors of same value in serial mode. It is nosense.
It is not nonsense.
Looking at the discoloration on the board I am going to guess that they (total of 6) are all 220Ω 1W resistors.
This is a way of distributing and dissipating up to 6W of power among many components over a larger area.
 

Thread Starter

canillas

Joined May 6, 2023
6
A guy in another forum explained me that 'L' could be a letter used during manufacturing process that shows the laser cut depth and those resistors have been scrapped off and can lost their upper film with the EIA96 marking code. So it is supposed that all those six resistor are the same 1206 - 221code type for dividing the power disipation, and perhaps make a voltage divider.
 

MrChips

Joined Oct 2, 2009
31,057
A guy in another forum explained me that 'L' could be a letter used during manufacturing process that shows the laser cut depth and those resistors have been scrapped off and can lost their upper film with the EIA96 marking code. So it is supposed that all those six resistor are the same 1206 - 221code type for dividing the power disipation, and perhaps make a voltage divider.
There is no sign of a voltage divider. As far as I can see, all six SMD resistors are connected in series.
 
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