Another local Ebay find was this Hewlett Packard HP 403B AC Voltmeter in a protective HP vertical case. The case did an excellent job of protecting the meter over it’s now 48 year life.Continue reading “Hewlett Packard HP 403B AC Voltmeter Restoration”
I found myself in need of a rechargeable battery tester, so I went off to search the internet for a DIY tester.
I was pleasantly surprised to find that John Lowen, had built a Rechargeable Battery Capacity Tester (v2.0), and also developed the PC interface software for desktop use.
Even better I found that Paul V. had also built the same tester and had made several improvement in the design and software.
Everyone should have at least two of these ESI 250DE Impedance bridges.
Well that was not my first thought when purchasing this unit on Ebay.
I was still having some issues with the “Internal DC” detector circuit on my existing unit, and the price of this unit was extremely reasonable. After dozens of hours troubleshooting the first unit with no solution, my thought was to compare the two circuits and salvage parts from the new unit if necessary.
An updated version of the Millivolt Meter project from May 2016, with dual range selection, calibration selection, improved software, and updated board layout.Continue reading “Millivolt Meter Version 2”