# How do I test schottky diodes ?

#### DarthVolta

Joined Jan 27, 2015
382
I bought a few 1N5711 schottky diodes off ebay, what can I try, with a scope, AWG, LCR meter, to see if they really are schottky diodes (which I need to learn up on anyways)

#### DarthVolta

Joined Jan 27, 2015
382
I built a simple version once with a little trans, is it that easy to tell it from that ? I'll give it try, I think I still have that OT ready to go once I find it.

#### MrChips

Joined Oct 2, 2009
20,856

#### DarthVolta

Joined Jan 27, 2015
382
Aside from being a smoother 60Hz than an AWG, what's the difference between using a little trans, and the AWG ?

#### MrChips

Joined Oct 2, 2009
20,856
No difference except transformer cost $1 while AWG costs$10k?

#### ronsimpson

Joined Oct 7, 2019
592
My meter has a "diode test" mode. The meter puts out about 1mA with a max voltage of 2V. A silicon diode reads 0.65 about and Schottkys read 0.35 to 0.45. (forward voltage drop) That is a good first test.

Next test is to see if it is leaking. The data sheet; "50V less than 0.2uA". Use a current limited power source in the 12 to 50V range and measure to see if almost no current is flowing. (could use a 9V battery)

#### crutschow

Joined Mar 14, 2008
24,706
The AC curve trace, as shown in post #4 will give both the forward voltage drop versus current and reverse leakage.

#### sparky 1

Joined Nov 3, 2018
116
I really like the switching speed on the 1N5711 because it can improve the symetry of a square wave off time to closer match the on time. The before and after on the scope is well worth it in performance.

#### DarthVolta

Joined Jan 27, 2015
382
Ok, yes I should have searched 1st

#### Papabravo

Joined Feb 24, 2006
13,456
Here are some LTspice sims for reverse recovery measurement. Run the sim and look at the diode current wavefrom where V1 switches from +24V to -24V

#### MrChips

Joined Oct 2, 2009
20,856
In the curve tracer video in post #4 the narrator made one error when he said the slope of the line is equal to the resistance.

Since current is on the Y-axis and voltage is on the X-axis, the slope of the line is ΔI / ΔV which would be equal to 1/R, not R.

A steep line will be the result when R is small.