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View Full Version : hey all another stupid newbie question trying to do things over his head lol



Badger
09-01-2008, 08:33 AM
Hello

i am trying to build a relay circuit i dont have a protection diode is would any of these items help me..

tip120 darlington transistor
mpf102 field effect transistor n channel
lm317t adjustable voltage regulator
irf510 mosfet transistor n channel = 60 volts
just a question on this one
Cermet Potentiometer ????
3n2904 npn transistor that comes with the parllarx HWD board kit
10 k ohm trimmers
ad5220 digital potientiometer


i know that this not a smart question and your patience is appreciated thanks .. I am poor broke. I am a sever arthritic and on lots of pain meds and i have to have surgery on tuesday and i just am trying t tink to get my mind off of pain and such. its a long story.. sorry for the boo hoo story but just to let you all know i am trying to push my self.

badger

PJ Allen
09-01-2008, 10:10 AM
Nope, nothing there can take the place of a diode, really.

( Somebody might have a "bright idear" and suggest using a B-E or B-C junction of one of your transistors, but I say, "Don't do it." )

Beau Schwabe
09-01-2008, 01:06 PM
Badger,

PJ is right, there's really nothing in you bag of parts that would be of use to replace a diode.

Badger, diodes are relatively cheap... use the right tool for the right job.

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Beau Schwabe (mailto:bschwabe@parallax.com)

IC Layout Engineer
Parallax, Inc.

Post Edited (Beau Schwabe (Parallax)) : 9/1/2008 7:42:26 PM GMT

william chan
09-01-2008, 09:46 PM
Badger mentioned he is broke and can't afford to buy a diode.
Anybody offer to donate him one?

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www.fd.com.my (http://www.fd.com.my)
www.mercedes.com.my (http://www.mercedes.com.my)

Beau Schwabe
09-02-2008, 01:44 AM
Badger,

If you connect the Gate to the Source of your irf510 it will function as a diode.... Notice I said the Gate and the Source should be connected.... This will allow the Bulk Diode to operate in parallel with the MOSFET. The other way,,, The Gate connected to the Drain ... will allow the Bulk Diode to function as a diode in one current direction, and the MOSFET to function as a diode in the other current direction.

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Beau Schwabe (mailto:bschwabe@parallax.com)

IC Layout Engineer
Parallax, Inc.

Post Edited (Beau Schwabe (Parallax)) : 9/1/2008 7:39:39 PM GMT

PJ Allen
09-02-2008, 03:02 AM
Whatever happens, happens.
I wash my hands of it.

Chris Savage
09-02-2008, 07:27 AM
Badger, please try using a descriptive subject line in future posts.

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Chris Savage
Parallax Engineering