I see
0.365 between cathode 1 and anode
0.365 cathode2 and anode

and the other direction shows:
.0L



It`s from computer power supply.

 

0.365 whats?
On what range of the meter?

I think they are Shottky diodes and they are good, but you really must provide more information.

 

Also, are these measurements done out of circuit?

 

Hello,

The BYC8 is a single diode.
The cathode is also connected to the tab.

Bertus

 

I am talking about Volts. Using digital multimeter in diod testing mode.

It`s not on the heat sink. It`s only diod which is not on any board

I think it is not Shottky because that`s not written in pdf

http://pdf1.alldatasheet.com/datasheet-pdf/view/16366/PHILIPS/BYC8-600.html

 

(( 30ns may be relatively fast for given currents (1 to 8A) why they call it ultra fast ))

drops up to 2.8V at 8A (22W)

 

So it`s good or bad?

I just know what should be the forward voltage as the rule for the diodes (silicon) - between 0.5 and 0.8.

 

the general thinking goes that in ?"normal" operating conditions the voltage drop on PN junction is something 0.6 to 0.8V
while in small signal oscillator circuits the lower limit for diodes is somehere 270mV and BE junction 380mV
depending on diode the large signal maximums may go over 2V

the good or bad depends where you intend to use it
as what i can come up from datasheet it's not used as rectifier rather reverse diode for mosfet or gate protection
random find for FR rectifier STPR1620 has somewhat half the voltage drop of that on BYC8-600
witch makes it more considerable to be used and for rectifier bridges - while the latter i wouldn't put there

 

I have one computer PSU and i have desoldered the heat sinks from the board and check the elements that are linked to them.

Took off the diod from the heatsink and want to check it.

 

if you go mad make it beneficial as energy source for staying alert
(join local martial arts club to get better insight while required)

what you did (FW conductance path verified, BW blocking verified) is usually sufficient

hypotetical : if your diode hadn't significant conductance at below 1V your std. meter's "diode FW cond. check" might had failed
so alternate procedure : is constant current or current limit and sufficient higher voltage voltage source
also may be needed for darlingtons´ base emitter FW conductance

 

I have never checked an isolated diode, with a multimeter, on the volts setting.

 

http://en-us.fluke.com/training/tra...o-test-diodes-using-a-digital-multimeter.html

 

So we go in this case
0>0.4V >> Short ?
I dont see the diod to be Shottky in the PDF so it has no excuses// to does show these voltage if it`s not shorted.

Sorry for my last Reply. I was nervous

 

i get nervous when the computers (world.processes) are slow - that means - almost uninterrupted
that's why i have to file my nails - they go numb of drumming the table continuously

 

It`s me again.

Prepare you tranquilizers

About the diod ok. I am pigheaded.

When i read about atx repairing i see on the heat sinks "some elements".

In them i dont see Bridge Rectifier with 4 pins. >> dont have info about them checking.

Is there a authoritative way to test it out of circuit and unmounted from heat sink ?

 

you're complicating your life coz your testing limits are set by an availability of the schematic you debug e.g. what nearby components can be shorted off / cut out from your test e.c. or you must already be experienced of testing it under limited operating conditions knowing the proper operational voltages at the check points + have a good equipment×methodology to know whether your test results are credible
?? re your question what ATX model# you have in hand - the component there
(the general solutions always more complicated than specific ones) ♪♫

 

http://www.electroschematics.com/6932/in-circuit-testing-of-diodes-and-rectifiers/

http://electronicdesign.com/lightin...d-forward-current-protect-sensitive-junctions

http://www.cliftonlaboratories.com/1n400x_diode_family_forward_voltage.htm

Alternate Diode test Google in Pictures

 

I see
0.365 between cathode 1 and anode
0.365 cathode2 and anode

and the other direction shows:
.0L



It`s from computer power supply.

 

the diode is o.k. a diode in a pwr supply usually shorts first, then breaks open due to excessive current.this is why, when tested,it shows an open

 

It`s gone a time from my last check of the thread. Now i read it again and maybe analyze the things other way.

I have buyd before time the NXP analogue of this Philips Diod.

Now i measure it and it has 0.409 between Cathod1/2 and Anode.

I have no reason to doubt in this piece goodness.

For one diod if it`s Silicon the dvm should show 0.5-0.8.

If it`s Shottky it is very lower - for example 170mV

There is some reason these pieces to have different voltage to basic silicon and shottky?

Is this "ultrafast" or "low switching loss"

And P.P

The PSU is Fortron Epsylon 700.

Thanks