I Think I've blown my Diodes ??

[rogerthebodger]

Re: I Think I\'ve blown my Diodes ??

[ QUOTE ]
Yes sorry Nibusgb I went and checked the LEDs I have on the data sheet 5v max reverse volts. I thought it was higher

[/ QUOTE ]

Interesting I have a number of 5mm red LED indicator on my mains distribution panel across the 240VAC feed with just a 0.5 Watt 15 K ohn dropper resistor which are working fine with no big bang.

Do not have a data sheet as purchased from local electronics shop so will be cheep cheep from china type.

 

[misterg]

Re: I Think I\'ve blown my Diodes ??

[ QUOTE ]
Yes sorry Nibusgb I went and checked the LEDs I have on the data sheet 5v max reverse volts. I thought it was higher. olewill

[/ QUOTE ]

Provided arrangements for current limiting are in place, reverse voltage shouldn't damage 'normal' LEDs. They do have a reverse breakdown voltage as pointed out, but exceeding this shouldn't damage the LED - they just act like zener diodes, and pass current in reverse, with roughly the stated voltage drop, but don't light up. (Need to be careful about power dissipation if your 'pushing the envelope', though.) Should work quite happily once the voltage has been swapped around again.

Andy

 

[Billjratt]

Re: I Think I\'ve blown my Diodes ??

For info on LEDs if anyone's interested:
I took MrGs advice and popped 100gnomes in series, so we now have 100ohms and a safety diode in series with an array of 2 strings, each of 3 LEDs, in parallel.
Bench testing - so no cable drop - the assembly now draws 5m/A, and is a little dimmer than it was, but at that current I can winter North of the Arctic Circle at anchor!
During the previous suck-it-and-see design phase, 2 LEDs in series worked happily across the battery (13v)
I'm quite happy not to have a super-bright anchor light as they pollute anchorages and spoil stargazing.