[volt-nuts] More Precision Resistors

[Robert Atkinson]

I picked up a DB-877 at the De Anza swap meet in the bay area a few years ago. It was grubby but a bargain at $40! Works perfectly after a bit of cleaning and some lubrication of the concentric shafts. These a realy good units, very compact for 8 decades. 0.01% is good enought for me as a decade box. The swap meet is well worth a vist. Dispite many vists to the bay area only on coincided with the meet.

Robert G8RPI.

--- On Sun, 16/8/09, Mark Sims <holrum at hotmail.com> wrote:

> From: Mark Sims <holrum at hotmail.com>
> Subject: [volt-nuts] More Precision Resistors
> To: volt-nuts at febo.com
> Date: Sunday, 16 August, 2009, 2:26 AM
> 
> I recently got in an ESI DB877 8 decade resistance box (12
> Megohms at 0.1 ohms/step).   This box is
> chock full of 0.01% wire wound resistors (1R and 5x2R
> resistors per decade) and a pair of nested four gang
> switches/dials.
> 
> The 1K resistor was pretty much toast.  I replaced it
> with the 900.98 ohm and 100.02 ohm resistors from a
> Tektronix 067-0503-00 precision DC divider (paralleled with
> a selected 1 Meg resistor).  That resistor is now
> within around 0.0005%.
> 
> The 10K resistor was also off,  reading around 10015
> ohms.  Paralleling it with a selected resistor pair
> also got it to around 0.0005%.
> 
> All is well with this wonderful little box and all values
> are now well within spec (0.01%).   Most are
> under 0.003%.  However,  things could be better
> for this volt nut.  The 100K and 5x200K resistors are
> all around 8-9 ohms high.  
> 
> Does anybody know of a cheap source of 1 to 5 gohm 
> resistors (actually 1.250 gohm,  1x2.500 gohm, 
> and 4x4.000 gohm,   would be best and would
> get that whole decade under 0.001%)? 
> Mouser/Digikey/etc have them for around 4 bucks a pop...
> cheaper is better...
> 
> Now,  if I could also find a -0.0382 ohm resistor to
> cancel out the zero ohm lead/switch bias...
> 
> ----------------------------------------
> 
> 
> _________________________________________________________________
> Windows Live™: Keep your life in sync.
> http://windowslive.com/explore?ocid=PID23384::T:WLMTAGL:ON:WL:en-US:NF_BR_sync:082009
> _______________________________________________
> volt-nuts mailing list -- volt-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
>