how do i test a schottky diode rectifier?

[matthmal]

Hi Guys,

I have a schottky diode rectifier SR1060 that looks a bit burnt. I tried to test it but I am not sure whether its good or not. The following are the results and datasheet of the component:

1 - 2 -> 150 ohms
2 - 1 -> 1660 ohms and keeps going up
2 - 3 -> 1890 ohms and keeps going up
3 - 2 -> 149
1 - 3 -> 000
3 - 1 -> 000



Thanks,
Matt

[domas]

Re: how do i test a schottky diode rectifier?

if it is inside SMPS and it is soldered in the board, where pins 1 and 3 are connected by pc b traces, which is normal in lets say atx psu's, measurements are fine. If you testing it outside of board, it is dead with those resistances. But i am nearly sure it is okay.

[matthmal]

Re: how do i test a schottky diode rectifier?

Thanks for your reply. The component was on the board when I tested it. So it looks like we are still not 100% sure if 1 to 3 are shorted or meant to be like that.

[budm]

Re: how do i test a schottky diode rectifier?

The diode is common Cathode and it is being used in parallel (pin1 and pin 3 are tied together and connected to one end of the transformer winding). It is always best to test the components off the board.

[matthmal]

Re: how do i test a schottky diode rectifier?

So should I test for the voltage and then remove from board and test the resistance?

[budm]

Re: how do i test a schottky diode rectifier?

You will test the Diode off the board with the meter to see if it is shorted out or if it has open circuits in both directions. If it is tested out good, then you troubleshoot the circuits to find out why the circuit is not working, you will want to know if parts are good or bad first.

[Kiriakos GR]

Re: how do i test a schottky diode rectifier?

So should I test for the voltage and then remove from board and test the resistance?

Set the meter to Diode range.

[Rome]

Re: how do i test a schottky diode rectifier?

I tested this diodes out of circuit with fluke DMM in diode range & the reading is 0.174 but I see in utube by NorCal its 0.4, so I think the 0.174 is bad

[budm]

Re: how do i test a schottky diode rectifier?

I tested this diodes out of circuit with fluke DMM in diode range & the reading is 0.174 but I see in utube by NorCal its 0.4, so I think the 0.174 is bad

That Vf Voltage is depended on if it is the LOW Vf rating or not.
What is the P/N so you can look up the spec sheet?

0.174 Both ways? How about the resistance reading? I always use the Ohm mode (beside the Diode mode) also to test the semiconductor devices.

[Rome]

Re: how do i test a schottky diode rectifier?

That Vf Voltage is depended on if it is the LOW Vf rating or not.
What is the P/N so you can look up the spec sheet?

0.174 Both ways? How about the resistance reading? I always use the Ohm mode (beside the Diode mode) also to test the semiconductor devices.

0.174 one way reverse no reading OL from pin 2 to 1 & pin 2 to 3

[budm]

Re: how do i test a schottky diode rectifier?

So what is the P/N so we can verify the Vf spec?
To do the real test, you will need to at least do the Break down Voltage and current leakage test.

[Rome]

Re: how do i test a schottky diode rectifier?

So what is the P/N so we can verify the Vf spec?
To do the real test, you will need to at least do the Break down Voltage and current leakage test.

It's FMW-24L dual diodes, thanks again budm

[budm]

Re: how do i test a schottky diode rectifier?

According to the spec, the Vf max at If of 5A is 0.55V Max. so at lower current the Vf will be less (Meter is has very low current drive). So to be safe you should replace it or get the new one and see what the Vf will be.

[Rome]

Re: how do i test a schottky diode rectifier?

According to the spec, the Vf max at If of 5A is 0.55V Max. so at lower current the Vf will be less (Meter is has very low current drive). So to be safe you should replace it or get the new one and see what the Vf will be.

Thanks budm

[cdrsteve]

Re: how do i test a schottky diode rectifier?

I have a similar issue with a Schottky bridge that I am trying to definitively determine if it is good or bad hopefully without sending off for a replacement/substitute for comparison. It is a D20XBS6 60V @ 20A thin in-line package unit. I am getting voltage drops in the range of .119 -.122. Attached data sheet shows Vf 0.63V max @ IF of 10A. The .119 that I am getting with a Fluke 73-III on diode test sounds a tad low. Not quite certain how to decipher readings I am getting on ohms function but they are very close to Matt's readings in all respects. Any ideas?

[stj]

Re: how do i test a schottky diode rectifier?

volt drop changes with current.

[cdrsteve]

Re: how do i test a schottky diode rectifier?

That part I do understand. I am just wondering how this device would be expected to react/perform in-circuit if I am seeing Vf's in this range doing a DMM diode test. Just how low of a Vf should one expect to see for a "low-Vf" Schottky bridge device during a DMM diode test? As you can tell - I have not had much experience dealing with these devices so be gentle !

[budm]

Re: how do i test a schottky diode rectifier?

If you look at the graph of the Vf for the diode which affect by the amount of current flowing through the diode, then you need to know what the current the Fluke is putting out when you test the diode.
Or you can hook 10V regulated power supply in series with 100 Ohms resistor, and the diode in forward bias mode, then measure the Vf of the diode, then measure the Vdrops on the resistor to calculate the current flowing through the diode.

[cdrsteve]

Re: how do i test a schottky diode rectifier?

If you look at the graph of the Vf for the diode which affect by the amount of current flowing through the diode, then you need to know what the current the Fluke is putting out when you test the diode.
Or you can hook 10V regulated power supply in series with 100 Ohms resistor, and the diode in forward bias mode, then measure the Vf of the diode, then measure the Vdrops on the resistor to calculate the current flowing through the diode.

Got it. Off to experiment. Thanks.

[budm]

Re: how do i test a schottky diode rectifier?

Got it. Off to experiment. Thanks.

Hands on experiment is one of the best way to learn.