Hi guys,

I was wondering, with so many of you here experienced in electronic projects, if anyone knows of a suitable replacement for a BAT82 schottky diode? I am supposed to use that diode but I cannot find it in any of the shops.

I figure I would ask here first in case any of you are familiar with it. If not then I will have to match the specs with other similar diodes myself.

The datasheet,
http://www.ortodoxism.ro/datasheets/...81_82_83_2.pdf

I am using it in a lead acid charger circuit. Thanks.

 

You can confidently use 1N5817,18,19 . data sheet at

http://www.onsemi.com/pub/Collateral/1N5817-D.PDF

__________________
Regards,
Sarma.

 

OK thanks Sarma. I will check if the shops have this.

 

I don't know how you can be confident without knowing the application. Your suggested replacement has about 10,000 times the leakage current and as much as 100 times the capacitance of the BAT81 series.
I think rngd needs to tell us how the part is used.

__________________
Ron (aka Rube)

 

Yes. I should have suggested a better device- but the O P has indicated its use--
"I am using it in a lead acid charger circuit."

Thanks for the suggestion that helps me to be more critical in future.

__________________
Regards,
Sarma.

 

A thousand pardons. I totally missed the application information. I guess I really am getting old.
In fact, the BAT81 series would be unuseable unless the usage is in a trickle charger for a small lead-acid battery.

__________________
Ron (aka Rube)

 

Please -- you are perfectly correct NOT about what you felt in this post- and i could have chosen a better device irrespective of the actual use. when suggesting an equivalent, i should be careful. this is because, the O P may generalise this advise and try applying tomorrow at some RF application for band switching. you are correct and need not be apologetic. in fact I should feel for it. All the best of 2008 Please.

__________________
Regards,
Sarma.

 

Quite right, he said it's for a lead acid charger but he didn't say what type, if it's a switch mode power supply the diode you suggested probably won't work.

__________________
I also post at the following sites:
http://www.stop-microsoft.org http://www.heated-debates.com
Screen name: Aloone_Jonez
And http://www.silicontronics.com, same screen name as here.

 

Glad you guys cleared your misunderstanding. The charger is a trickle charger charged by a solar panel. So the 1N5819 diode can be used, right ? The circuit is attached below just in case. It is designed by someone named Oscar.


ps. I have a quick newbie question, what is the difference between the two MOSFET symbols in the second attachment ?

Thanks !

Attached Images

	chargercircuit.JPG (34.7 KB, 16 views)
	untitled.JPG (4.4 KB, 8 views)

 

The two BAT diodes are just to clamp the input to the op amp to about +/-0.4V.

The two MOSFETs are the same type, ref drawing, just drawn that way for convenience..
The 'arrows' direction on the FET's indicate a different type.

Attached Images

screenhunter26.jpg (13.6 KB, 8 views)

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

I would also connect one of the inputs of the unused comparator to +15V and the other to 0V.

__________________
I also post at the following sites:
http://www.stop-microsoft.org http://www.heated-debates.com
Screen name: Aloone_Jonez
And http://www.silicontronics.com, same screen name as here.

 

OK, thanks for the help.

 

There is an object lesson here. The lesson is, most noobs post too little info, rather than too much. If you had posted the schematic in the first place, we would have told you to use 1N4148's. The 1N5917 is one of the poorer choices for this application, although it should work.

__________________
Ron (aka Rube)