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Old 06-03-2011, 12:43 PM   #288 (permalink)
Freyguy
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Quote:
Originally Posted by ianbartie View Post
My variable power supply only goes down to 1.34V but I can make up a simple 0-2V tester with a couple of batteries & a variable voltage divider.
Need to go & finish putting in the new, super quiet, vacuum pump first.
Try putting the power supply in series with a 1.5V cell battery. Power supply negative to battery negative. Then use the battery positive for your ground reference. Relative to this battery positive, the power supply positive can now go a bit below ground.

BTW- What brand of pump is it? My Thomas is a noisy bugger, even after putting in a padded enclosure.
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