26-07-2011, 08:45 PM
(26-07-2011, 10:00 AM)martyb123 Wrote: the pot on the front panel was there to make it easy to set the fsd on the meter before you started to use it to test caps so if you put in the drawer for a year you would need to get to that pot knob to re-adjust the fsd before you used it again just incase the 9 volt batery had dropped significantly whilst in storage
The original designer never ran it off a 9V battery Marty - only four nicads, which - whether the meter was used or not - would self-discharge in a couple of months or so, never mind about year. And he never had any voltage stabilisation, which is why he said in his update in SEPT 2009: 'The zero of the meter tends to drift with changes in voltage'. Hence he needed a a front-panel control to tweak it for FSD as the voltage dropped over time. Fitting a voltage regulator obviates the need fo a front panel control - if FSD cannot be achieved it means the P3 battery has run down!
I think we've probably exhausted any useful coversation on this now, but when I've updated the PCB track layout to include 'C8', Ill post the amended artwork on the forum, should ayone wish to build th project.
Thanks for your valued input Marty, and best of luck with your meter.
David
