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Article #1622Re: Understanding a split-mode power supply.
From: Phil Allison
Date: Tue, 06 Jan 2009 03:48
Date: Tue, 06 Jan 2009 03:48
57 lines
2796 bytes
2796 bytes
"Sylvia Else" > Phil Allison wrote: >> "Sylvia Else" >>> >>>> >>>>> As for whether I could substitute a 6.8, maybe I could, though I'd >>>>> have trouble getting one that has a 350 volt rating. >>>> >>>> ** Huh ?????????? >>>> >>>> No need for that whatsoever. >>>> >>>> In operation, the resistor is not subjected to more than a few volts. >>> As I commented earlier, if the switching transistor fails by shorting >>> out, then the resistor will blow. After it's blown it'll have 340V >>> across it. >> >> ** Irrelevant. >> >> Once it has fused, the resistor will be OPEN circuit. > > Which just means it won't conduct unless the voltage across it exceeds its > insulating properties. ** No, it WILL be open circuit to the voltage that caused it to fuse. Cos the fusing behaviour will not cease until the part becomes open circuit in the given situation. >> The voltage across the break can be thousands of volts. > > So you say, but where's the evidence? ** You came here for the advice of folk with experience of electronics, cos you have none. That advice is based on many decades of ACTUAL experience, in my case. If you simply replace the fusible resistor in the PSU with a similar part, then it will work as well as the original one did. BTW: The maker's max voltage rating relates to a functional resistor - not a blown one. There is a HUGE amount of electronics YOU have no clue about. ..... Phil
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