[volt-nuts] Completion of LED Mod's for the Fluke 845AB & 845AR Null Meter.

Joe Hobart nova at npgcable.com
Sun Nov 23 14:51:32 EST 2014


I have a noisy 845AR, so I am keenly interested in your modifications.

Thank you,
Joe Hobart
Flagstaff, Arizona

On 11/23/2014 11:29 AM, Dallas Smith wrote:
> To All,
> The final modification of the Fluke null meters with LED's is completed. The
> results is impressive, keeping the basic original circuit of the meters. My rev
> 8 AR version has a double diode in the output stage which seems to remove the
> zeroing hysteresis around a zero reading was also made to my 845AB. Implementing
> two 1.2v reference diodes in the zeroing circuit greatly improved the zero drift
> for the zeroing control. There were also changes to the feedback response by
> changing two capacitors. If anyone is interested, please E-mail me at my
> personal address.
> dosmith at outlook.com
> Dallas

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