DIY_EFI Digest V4 #386

[Steve Ravet]

> 
> Date: Tue, 29 Jun 1999 21:50:11 +1000
> From: "Geoff Richards" <geoffsue at one.net.au>
> Subject: led O2 sensor
> 
> I have a 10 led o2 sensor that is commonly known to the list
> I would like to be able to check the operation of each individual
> led by applying the correct voltage to the signal wire.
> My question is how do I make a SIMPLE variable voltage source
> for this.
> I have very LITTLE understanding of electronics so to any folks
> kind enough to reply BEWARE it will need to be basic
> I posted a similar question to a newsgroup and received an answer
> that I really do not understand but would be able to send to anybody
> willing to help out.
> Cheers
> Geoff

Geoff, try this:  take a regular 1.5V battery (C,D,AA, whatever).  Get a
potentiometer from the Australian equivalent of Radio Shack.  The value
doesn't matter too much, something from 10k-50k should be fine.  Get one
that says "linear taper".  Don't get "audio taper", "log taper" or
anything like that.

Hook it up with the battery across the end terminals of the pot. 
Connect your LED meter to it's usual power source.  Also connect the
ground or common side of your LED meter to the negative terminal of the
battery.  Finally connect the middle terminal of the pot to the LED
meter signal input.  As you turn the pot, the signal voltage will vary
from 0-battery voltage, about 1.5 volts.  You should see the meter move
accordingly.

--steve

> 

--
Steve Ravet
sravet at arm.com
Advanced Risc Machines, INC
www.arm.com