Imagine the perfect diode. It would have a zero forward voltage. Well, in a tightly controlled environment (complete with dodgy heat gun) that goal has been achieved!
By Julian
Youtuber, shed dweller, solar charge controller aficionado
For rectifying, now mosfet-based synchronous rectifier have already invented.
Hi i have here a TV with power supply with a Blown fuse and i checked a schottky diode 2D-02 and i test in circuit it tests short when i take out of circuit i tests open,with my fluke in diode setting,is this normal or is it bad ?
you should also measure the reverse current leakage when it gets heated. it's awfully high. 🙂
Can you tel me what Schottky Diode have you used? Thanks.
I just bought Schottky diode today, rated to carry 3amps. I measured the resistance of this diode and it was 84ohms. Why so much resistance?!
Heh, this CAN happen in circuits, it is called thermal runaway. The diode heats up, and the forward voltage drops, allowing more current to flow through, heating it up more. This is assuming you have two 3A diodes and parallel and you are running 6A through them….. OK, right?! NOPE!!! This will happen…
I wiki'd it – complicated stuff
Fermi level.
I didn't test reverse voltage, but a later video shows that the reverse current leakage gets very large when hot. So the diode ends up like a piece of wire, conducting in both directions.
does it still function as a diode when its heated, the FDV went to 0 but was it still blocking reverse voltage at that point
I'm expecting the forward voltage increase due to high forward current to dwarf the effects of heating. So I think you're right; once a large current is flowing, this temperature effect will be of no benefit.
You'll get a higher voltage dropped over the diode as you increase the current, so presumably you would have to apply more & more heat as you go. At some point the diode ain't gonna like that! heh. Perhaps putting the diode in a glass jar up by the panel so it gets sun on it might help. The ultimate zero voltage drop blocker though is a relay that simply turns off when the sun goes down. These solutions are unnecessary in most cases though as charge controllers usually take care ov the blocking.
Check out the LX2400ILG (solar bypass device) —> 60mV drop @ 10A.
Well it seems fascinating. Which semiconductor and metal you used for schottky junction? Thanx