help matching irfp240 and irf9610

[MikeZ]

I know its another post about this....SORRY....

I am using a 12 volt battery charger, what value of resistor do I use and what does the wattage of the resistor need to be?

I read of someone using a car charger in the forum, I searched and could not find it.

Thanks so much for your help.

Mike Z

[uli]

Hi Mike,
depends on the current. IRF9610 10mA (Aleph)
woulde be about 820R if the 12V are stable.
IRFP 240 I would take 82-100R for about 100mA.
Uli

[hifi]

hello,

you cant use a car battery charger since they don´t use pure DC,

/micke

[Mark A. Gulbrandsen]

MikeZ....the battery charge is a bad idea....not only cause its not pure dc, but because it won't be a stable source of voltage or current. You should check e-bay for a cheal used bench supply capable of at least 12 volts dc at 1 amp or so. Even a used chassis mounted oem supply will work.

Something reasonably priced like this...or you might even borrow one from a friend.....
http://cgi.ebay.com/ws/eBayISAPI.dll...category=11772

[Tim F]

I can understand why a mains powered battery charger will not be ideal but would it not be possible to use a StarterBooster/Charger the type with the gel battery in & usually an accessory socket on the outside.
It's only a thought from a newbie.

[Mark A. Gulbrandsen]

It just has to be stable over the time period that you are matching devices. Also if you need to go back and match some more at a later date then you have to duplicate the same operating conditions to match to what you already have done. As an alternate he could outboard a simple IC regulator...LM317.... on the output of that. Then it may well be stable enough.....and that should cost less than 10 bucks!
Mark