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Identify component L2

BillyWhiz

May 22, 2023
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Hi Y'all,

I have found a short circuit on the component L2 but I don't know what it is? it looks like a diode..

Kind Regards,
Billy
 

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Delta Prime

Jul 29, 2020
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L2 on a PCB silk screened and written on schematic's refers to a component that has inductance, whose value would be in Henry's. That's the fancy way to describe a coil . By the way you see L1 there's nothing there no coil no inductor. For DC inductors will show up as a short circuit this is normal there is a DC resistance to the coil but as you discovered the resistance is so small your meter thinks it's a short circuit. What you must do is get a LCR meter and measure it's inductance.
So unfortunately this component
Would check okay to me if I was troubleshooting and I would move on something else is wrong.
I misspoke un-solder one lead of L1 that inductor and check again
 
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BillyWhiz

May 22, 2023
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Hi Delta Prime,
Thank you for your reply, I checked L2 with my meter and it comes up as a resistor with 0.04 ohm, also There was a inductor with 1.53mH in L1 which looks like a resistor!
 

Delta Prime

Jul 29, 2020
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Okay just for kicks and giggles un-solder one leg and retest please .
 

Delta Prime

Jul 29, 2020
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Well put them back! Just kidding what seems to be the problem you are having is it visually L2 looks like a diode and L1 looks like a resistor photos please
 

Delta Prime

Jul 29, 2020
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I checked L2 with my meter and it comes up as a resistor with 0.04 ohm, also There was a inductor with 1.53mH in L1 which looks like a resistor!
Then L2 should have an inductance along with it as wel and vice versa what is the DC resistance of L1
 

BillyWhiz

May 22, 2023
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The top (Black) has come from L2 and reads as a resistor, and the bottom which looks like a resistor is the one that reads as an inductor?
 

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Delta Prime

Jul 29, 2020
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You're multifunction tester tc1
Apparently this is your inductance meter
 

BillyWhiz

May 22, 2023
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Confusing why this reads as a resistor when its completely black?
 

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Delta Prime

Jul 29, 2020
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Stay with me... concentrate... pay attention... we can find out right now inductors add when put or connected in series
Just like resistors they add as well when put in series. Therefore we already know the inductance of L1 add L2 in series with L1 measure the total inductance.
 

Delta Prime

Jul 29, 2020
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While you're making those measurements. I just realized I sound just like my old professor.
 

Delta Prime

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Well then let this be a lesson to you I got to go to bed... sorry buddy someone will be a long shortly. Good night.
 

kellys_eye

Jun 25, 2010
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It's not really an inductor - it's a ferrite suppressor, just a piece of wire passing through the core of a piece of ferrite. OK, that's 'really' an inductor but the value will be smaaaaallllllll. Either way it reads short-circuit normally and your circuit will likely work even if you remove it and replace it with a short length of wire (but I wouldn't do that).

Very, very unlikely it's dud. What is the issue that made you suspect it in the first place?
 
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