| Electronics > Repair |
| 1N4148 diode spec's |
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| Jeff eelcr:
I seem to remember some had different voltage ratings? Is there a way to tell in the markings or were these fake parts? Working on a Peavey CS-800 amplifier for a friend who is suppling parts, I received a batch of 1N4148's from him. These were marked V 4148 and were slightly smaller than ones I was replacing so it made me think to test them. At slightly over 40VDC these exploded open, others I had in stock were still fine at slightly over 60VDC, these were marked H 1N4148. Can you guess what would have happened if I had used what he got without testing them. |
| ArdWar:
--- Quote from: Jeff eelcr on June 14, 2024, 01:32:12 am ---I seem to remember some had different voltage ratings? --- End quote --- Yes, somewhere between 75V to 100V. --- Quote from: Jeff eelcr on June 14, 2024, 01:32:12 am ---Is there a way to tell in the markings or were these fake parts? --- End quote --- Not really in practice. Most just got generic marking. --- Quote from: Jeff eelcr on June 14, 2024, 01:32:12 am ---Can you guess what would have happened if I had used what he got without testing them. --- End quote --- Depends on where and what the diodes are supposed to do. Are you sure there's nothing else wrong with your gear? Engineers don't usually design commercial product in such a way that stress a generic jelly bean part anywhere near their limit. |
| Kim Christensen:
Probably fakes... The Vishay ones marked V4148 are rated for 75V What would have happened? Maybe nothing. Depends on the circuit and if they'd get reversed biased with more than 40V. Best to not use them though. Who knows what the other specs are. |
| DimitriP:
--- Quote ---Can you guess what would have happened if I had used what he got without testing them. --- End quote --- Yes, you would stop accepting "friend supplied parts" in the fist place :) Or as they are known in other circles: "customer supplied parts" On a different note..Peavy sure like their diodes !!! |
| MathWizard:
I forget I should never really trust ebay/amazon parts. I've said it before but never did it, I should test some of my diodes and BJT's. I mainly get brand name electrolytic caps these days, and I can think of a few old things I made that should get better caps too. |
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