Safe to replace 1N4004 with SY 320/8?
Posted by anwe79
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Safe to replace 1N4004 with SY 320/8? January 25, 2012 12:28PM |
Registered: 12 years ago Posts: 80 |
Hi, i just got my RAMPS 1.4 kit and am soldering it up now. I came to the point were the diode is put in and realized i'm missing the 1n4004 in my kit. Don't know if it was missing from the supplier, but anyway...
I went through my boxes of scrap and found some SY320/8 diodes. I'd like to use these so i don't have to go shopping for a measly diode.
A quick google tells me they're rated for 1040 V, 2A which should be plenty, but i'm not sure what the function of D2 is in the circuit. I think these should be way overspec, but they have a larger voltage drop 1,2 V instead of the 1,0 V of the 1N4004.
Will this cause problems in the circuit?
I'm only going to use D2 for now, I'll se later if I'll need to power the arduino via the RAMPS and have to use D1 as well.
PS: Data for SY 320/8 found here...
Regards
Andreas
I went through my boxes of scrap and found some SY320/8 diodes. I'd like to use these so i don't have to go shopping for a measly diode.
A quick google tells me they're rated for 1040 V, 2A which should be plenty, but i'm not sure what the function of D2 is in the circuit. I think these should be way overspec, but they have a larger voltage drop 1,2 V instead of the 1,0 V of the 1N4004.
Will this cause problems in the circuit?
I'm only going to use D2 for now, I'll se later if I'll need to power the arduino via the RAMPS and have to use D1 as well.
PS: Data for SY 320/8 found here...
Regards
Andreas
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Re: Safe to replace 1N4004 with SY 320/8? January 25, 2012 10:58PM |
Registered: 14 years ago Posts: 196 |
The purpose of D2 is to act as a short in the case that the 12 volt power supply is connected to the RAMPS board backwards. In this case the short will draw excessive current causing the resettable fuse to trip. The goal of all this is to protect the rest of the circuit from the reverse voltage.
If you are certain that you will not connect the 12 volt power supply backwards then you can safely leave D2 out of the circuit without any ill effects.
Based on the information you have provided about the SY 320/8, it should be a workable substitute for the 1N4004.
If you are certain that you will not connect the 12 volt power supply backwards then you can safely leave D2 out of the circuit without any ill effects.
Based on the information you have provided about the SY 320/8, it should be a workable substitute for the 1N4004.
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Re: Safe to replace 1N4004 with SY 320/8? January 26, 2012 06:15AM |
Registered: 12 years ago Posts: 80 |
Thank you for your answer madscifi, that's what i thought.
I did a bit of googling last night and came to the same conclusion. If anything, the "bigger" diode should be more resilient if the polarities actually are reversed, since it can handle a bit more current and will fail later if the fuse doesn't blow quickly enough.
As a bonus I learnt to check the protection diode(s) in case a fuse blows, since they may have taken a beating. If they fail open circuit, they're no longer any good for protecting the circuit, but will seem to operate normally. If they fail short circuit, they will continue to blow fuses which is more obvious of course.
The voltage drop should be of negligable importance, since it's not in series with the supply (and even then 0,2 V extra would probably not be anything to worry about).
Regards
Andreas
I did a bit of googling last night and came to the same conclusion. If anything, the "bigger" diode should be more resilient if the polarities actually are reversed, since it can handle a bit more current and will fail later if the fuse doesn't blow quickly enough.
As a bonus I learnt to check the protection diode(s) in case a fuse blows, since they may have taken a beating. If they fail open circuit, they're no longer any good for protecting the circuit, but will seem to operate normally. If they fail short circuit, they will continue to blow fuses which is more obvious of course.
The voltage drop should be of negligable importance, since it's not in series with the supply (and even then 0,2 V extra would probably not be anything to worry about).
Regards
Andreas
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