A hammer. If you get frustrated with a circuit, you really don't want one of these within easy reach.

The worst tool would be using philips screwdriver with a battery as a soldering iron. Because first thing it never works and second there is a great chance that it will give you a shock and might burn your fingertip for a while.

My father and I enjoy model trains. A while back the club we belong to decided to remodel several areas of the layout.  In the chaos that is 15 different people working on a project with poor communication a section of track was wired with a shorted circuit. A member of the group who claimed to be an electrical engineer decided to locate the section of track in question by applying 120vac directly to the completely exposed rails of the entire model layout. While thankfully no one was electrocuted from the extreme over voltage on the 12vdc track, the section of track shorted quickly melted and released its smoke. The resident "electrical engineer" was voted out of the club shortly after as a measure to preserve life and layout.

Toothpick      

Toss-up between the wire stripper (a good pocket knife serves me butter) and a soldering iron (pretty sure that's only a me issue; maybe I just need more practice?)…

Many many years ago, when I was working at an Aladdin's Castle arcade, I noticed a problem with one of the upright video game machines.  The video image was a bit shaky, and I couldn't resolve the issue by tweaking any of the video controls on the monitor like is typically done.

So, with that in mind, I set about trying to see if there was a capacitor or other component with something loose inside or maybe a loose wiring harness that maybe I could fix after powering off the machine.  Obviously, I couldn't see if I was having any luck unless I left the machine on, so I set about shaking wiring harnesses first with no luck.  Next, I tapped on board-mounted capacitors with no luck.  Now, this obviously happened back when all video games had tube-type monitors, so anyone who's worked on an old TV or monitor should be able to relate to what I'm about to explain.

Getting a bit frustrated, I started tapping on chassis-mounted transistors...thinking that I had been told in my high school electronics class that anything mounted on the metal chassis should be at a ground potential.  I found one on the side of the monitor chassis that definitely wasn't at a low level, but felt like it was instead at some potential closer to the voltage on the flyback transformer because it tossed me across the sales floor and into the side of a pinball machine.

I uttered a couple of choice words as I sat on the floor before I realized that there were sensitive ears present and then apologized for my indiscretion.  Shortly after, I shook off the shock of being tossed around and then stood up and finished my day.

It was pretty obvious that a bare finger was not the optimum tool for checking for loose or damaged components inside a functional video game.

That incident also taught me never to trust anything on the side of a monitor chassis again.  Nothing inside a tube-type monitor is as it seems.  It makes me glad that we've gone to LCD's for sure!

I have found that water doesn't work well as a tool with electronics.  And I have found mineral water is worse than purified water.

So stay away from water as a tool.  In addition to electronics breaking when using water, you may also cease to function / stop working. 

-brian

YouTube video blogger that well got it wrong!!

colporteur

dougw  wrote:

 

And then there is using your tongue to determine how much juice is left in a 9V battery...

Still do it . . . . . . . . there have been deaths believe it or not, probably someone doing it at the top of a ladder and then falling . . . . . . . I make sure I'm sat down first, just in case.

Brave Shabaz? or stupid . . . . . .