schottky doide

I know the schottky diodescan have vf up to 0.15v. but I have a sbl 304opt rectifier and it's forward voltage is 0.110 v . and it's too small and it has about 40kohm resistance in reverse and 500ohm in forward mode. are these measures suspect.?and this rectifier is for my pc's power supply that neither work nor have 12v voltage at all and all other related devices are intact.

Did you measure the diode in or out of the circuit?

A DMM (Digital Multimeter) can be used on the diode test mode to check your diode. In that mode it runs 1 mA through the diode and reports the voltage drop.

definitely out of the circuit and it is quite clear that in both diode test mode and then resistance mode for certainty!. I just want to know if these values are normal for an intact schottky diode or not?

Let's assume your DMM applies 1 mA with a compliance of 6 volts. Referring to the datasheet Fig. 3 we see that the curve goes down to 10 mA and not 1 mA. But at 10 mA the forward voltage is 0.2 volts. From this we can conclude that at 1 mA you should measure close to the 0.15 volts you measured.

Referring to Fig. 4 we see that at 6 volts reverse the current is 20 uA. The resistance measured with 6V/40uA = 150k ohms and is in line with the 40k ohms you measured.

Your diode appears to be good.


http://www.vishay.com/docs/88732/sbl3030pt.pdf