Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering Magazine Articles Engineering software RF Cafe Archives Magazine Sponsor RF Cafe Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Alliance Test Equipment Centric RF Empower RF ISOTEC Reactel RF Connector Technology San Francisco Circuits Anritsu Amplifier Solutions Anatech Electronics Axiom Test Equipment Berkeley Nucleonics Conduct RF Copper Mountain Technologies everything RF Exodus Advanced Communications Innovative Power Products KR Filters LadyBug Technologies PCB Directory Rigol TotalTemp Technologies Werbel Microwave Windfreak Technologies Wireless Telecom Group Withwave Sponsorship Rates RF Cafe Software Resources Vintage Magazines RF Cafe Software WhoIs entry for RF Cafe.com Thank you for visiting RF Cafe!
Copper Mountain Technologies (VNA) - RF Cafe

Werbel Microwave (power dividers, couplers)

Amplifier Solutions Corporation (ASC) - RF Cafe

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

RF Cascade Workbook for Excel

RF & Electronics Symbols for Visio

RF & Electronics Symbols for Office

RF & Electronics Stencils for Visio

RF Workbench  (shareware)

T-Shirts, Mugs, Cups, Ball Caps, Mouse Pads

These Are Available for Free

Espresso Engineering Workbook™

Smith Chart™ for Excel

Berkeley Nucleonics Vector Signal Generators Radar Simulations - RF Cafe

Out of Order: Low Battery in Multimeter = High Voltage Scare

Out of Order: Tech Trials & Tribulations - RF Cafe

RF Cafe University"Factoids," "Kirt's Cogitations," and "Tech Topics Smorgasbord" are all manifestations of my ranting on various subjects relevant (usually) to the overall RF Cafe theme. All may be accessed on these pages:

 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37

The very first submission for RF Cafe's new Out of Order feature has been received from Joe Birsa. His experience is one that many of us (including me) has been bitten by at some point in our electronics and/or electrical pursuits. Unfortunately, this type of situation occurs so infrequently that by the time it happens again, we've forgotten about it and are prone to getting bitten once more. Do you have a good work-related anecdote to share? Please email it to me for consideration. Thanks.

 

 

 

 


Low Battery in Multimeter = High Voltage Scare

 

By Joe Birsa  N3TTE

Last year when I was adding a new accessory to my ham radio station at home, I noticed that the power supply I use for accessories was putting out 16 VDC instead of the nominal 12 volts I expected.

So, I turned on my soldering iron and grabbed a 7812 (a much-used linear voltage regulator), a scrap of project board, and a heatsink from my stockpile of parts and made a little voltage regulator.

When I then checked my voltage regulator, its output was also reading 16 volts! Suspecting a malfunctioning meter, I then used a new 9 volt battery to check my multimeter's accuracy. Rather than measuring a little over 9 volts as it should, it read 12 volts instead.

I replaced the 9 volt supply battery in my multimeter and the power supply then read the expected 12 VDC and the battery read 9 VDC. I then measured the battery I took out and it read low, about 7 volts.

Apparently the voltage reference in the multimeter required more than 7 volts in order to function properly. Seven volts wasn't low enough to prevent the meter from working, but it made every voltage reading display as being higher than it really was. A simple "LO BATT" indicator on the display would have save me a lot of trouble.

In retrospect, I should have grabbed my backup multimeter and verified the reading; but it was at night after a long day at work. Hopefully my experience will come to mind if you ever find yourself getting nonsensical readings during a measurement - do not just assume your test equipment is functioning properly.

 

Out-of-Order Archives

Do you have a good work-related anecdote to share? Please email it to me for consideration. Thanks.

- The Singing Telephone Switch 

- The Professor-Provided Cheat Sheet

- TV DXing, and the Dog on the Roof

- Occam's Razor for Water Bottles

- Of Pointy-Haired Bosses

- Attack of the Cookie Monster

- Tracking Down a Mystery Signal

- Low Battery in Multimeter = High Voltage Scare

 

 

Posted February 12, 2014

DC-70 GHz RF Cables - RF Cafe

About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024

Webmaster:

    Kirt Blattenberger,

    BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

Copyright  1996 - 2026

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website: AirplanesAndRockets.com

My Daughter's Website: EquineKingdom

RF Electronics Shapes, Stencils for Office, Visio by RF Cafe

Anatech Electronics RF Microwave Filters - RF Cafe

Rigol DHO1000 Oscilloscope - RF Cafe