POT circuit/connection

[ron5526]

ok, I'm going to try my hand at variable timing with the use of a POT, however, I'm having trouble trying to figure out how to hook the thing up.  The code looks like I can handle by looking at other posts etc (and the help of my Prop-1 trainer....blow the dust off).

I have/need the following:

POT  (Jameco 264411  10K 1/2watt)
Capacitor  (will be getting a .1uF)  never used one before

Now my problem, the POT has 3 connections.  At this point in my newbie POT experience I figure on hooking the thing up this way.

P7 (W) - connect to one end of the POT (figure a resistor at either end is the same)
P7 (B)  - connect to capacitor
P7 (R)  - not used
Other end of capacitor - connect to BOTH (???) remainig  terminals of POT

I figure on using my trainer board first the go for the above hook-up.

One other note:  I will be using a POT, PIR, & RC-4.  I suppose I will need to remove two legs on my ULN and redirect P5 as an input.?.

Thank you.
Ron

[JonnyMac]

You've got it all figured out, Ron.  Once you get your pot circuit connected, run the Pot Scaling function (in the Run menu) to determine the proper scale value for your pot circuit components.  With 10K and 0.1uF it should be around 100 or so.

[ScaryTinker]

Can you provide one of your Corel illustrations showing the hookup to a Prop-1? (I think I let the magic blue smoke out of one of the pins by wiring it wrong)

[gadget-evilusions]

ScaryTinker,

Here is a picture of what I normally build. I have used about 50 of these and they all have worked.

[JonnyMac]

Steve,

If Brian's image isn't quite there for you let me know and I'll break out Corel.  You can see what he's doing:

1) Cut one connector off a 14" extender cable
2) Solder the black wire to the pot's center lug
3) Solder the white wire to one side of a 0.1uF cap; the other side connects to the right-most lug
   -- when pot shaft is facing away from you
   -- this configuration means the pot value goes up as you turn the pot clockwise
4) discard the red lead; it is not used.

[ScaryTinker]

Thanks guys.  A picture is worth a thousand words.  I've got it now.   Now can you tell me how to put the magic blue smoke back in the chip?

[JonnyMac]

With magic, of course!