I used woot often. UPS sale today! https://computers.woot.com/plus/cyberpower-battery-backup-systems-42
On Sat, Dec 30, 2023, 17:57 Keith Lofstrom <[email protected]> wrote: > Many laptops have some sort of stereo audio input jack. > I can imagine a resistor+capacitor kludge that > attenuates the "hot" and "neutral" legs of a power > cord down to the stereo input levels. > > A program on the laptop captures hot and neutral voltage > waveforms, differences them, and (somehow) uses the > digitized audio signal to characterize the voltage > waveform quality produced by the device the cord is > plugged into. Perhaps logging the waveforms to disk > on the laptop, for long term monitoring. Sub-sampling > at 600 samples per second and 16 bit resolution, that > is 40 gigabytes per year, more than enough to capture > "rare but too-interesting" power glitches over time. > > If someone wants to write the program to do the > differencing and logging, I can put together a few > cord-and-resistor-and-stereo-plug kludges, and trade > hardware for software. The result would be a portable > setup for evaluating the waveforms produced by a UPS > in service, or a candidate UPS in the store. > > Besides evaluating UPS waveforms and behavior, it might > also be interesting to look for time correlations in power > waveforms between different locations around the Portland > area. An office in an industrial area might see subsecond > line voltage sags when a nearby factory is arc welding. > I can imagine those driving some computer power supplies > and UPS units batty. > > Keith L. > > -- > Keith Lofstrom [email protected] >
