mcbmcb0 Posted August 18, 2014 Report Share Posted August 18, 2014 HelloI'm fixing a 19" monitor switchmode supply which has a shorted schottky diode, type SB5150. That's a hard part to find where I live, so I'm wondering about replacements.SB5150 is a Schottkey Barrier diode rated 5Amp and 150V reverse voltage. But why so high spec? The LCD monitor supplies 12V (for backlights - maybe 1amp) + 5V (for video/audio) and it looks like a standard supply layout with this diode is on the low voltage side. So why 150V 5 Amps? I'm wondering if I could get away with a smaller device like 3A 100V (or less)...?But on the other hand if it was over-rated then why did the original die?Also, after quite some googling I'm still not clear on a Schottky Barrier vs 'normal' Schottky diode other than junction capacitance... but I don't understand the implications of this. I have urges to stick in any old diodes I find in some dead computer PSUs and hope it works....?????Can someone familiar with switchmodes comment on likely substitutes?thank youMike Quote Link to comment Share on other sites More sharing options...
indulis Posted August 19, 2014 Report Share Posted August 19, 2014 You have to consider what the anode voltage will be when the diode is not conducting (when it swings negative). Also any spikes that may be there. Quote Link to comment Share on other sites More sharing options...
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