I have a 1N4148 diode. I can not find which is the anode and cathode from datasheet.
Does anyone know where is the anode and cathode of this diode are?
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8\$\begingroup\$ Have you tried to check the polarity with a multimeter? \$\endgroup\$– Elec1May 2, 2021 at 13:27
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8\$\begingroup\$ I've never seen a diode with that line marking where that line did not signify the cathode. \$\endgroup\$– DKNguyenMay 3, 2021 at 6:24
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4 Answers
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The way I remember it is I think the line is the cathode line from the diode schematic symbol. See picture below where I drew in the diode symbol.
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Strange indeed that Diodes Incorporated datasheet does not contain the words "cathode" or "anode". Conventionally the cathode(-) side of the device is marked with a bar. So in your figure, it's the left end of the device. The "JP" and "YM" may be replaced with other letters or numerals, but the vertical bar stands for an actual vertical bar marked on the package.
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I would expect the left end, with the vertical bar, would be the cathode.
With other diode packages, the cathode is marked with a stripe.
answered May 2, 2021 at 0:49
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4\$\begingroup\$ Thanks Peter.... I think you are right. It is disappointed that there is no mention of that in the datasheet. \$\endgroup\$ May 2, 2021 at 0:52
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4\$\begingroup\$ @HossamFattah The cathode band marking is part of the SOD323 package specification. The data sheet doesn't mention it because it is not specific to the part number. \$\endgroup\$ May 3, 2021 at 4:27
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2\$\begingroup\$ @alephzero good point. Here is Diode Inc's data sheet for the package diodes.com/assets/Package-Files/SOD323.pdf it says "polarity: cathode band" \$\endgroup\$– RodneyMay 3, 2021 at 12:14
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Another data sheet for the 1N4148WSF states "Color band denotes cathode"
https://datasheet4u.com/datasheet-pdf/LITE-ON/1N4148WSF/pdf.php?id=1345127
