Using a cheap multimeter almost cost me my life one night.  I received a call from a good friend one evening who was having trouble with the lights flickering in his house,  also an electric heater he had plugged in was popping its reset button constantly. I grabbed some basic tools and went over to his place to try and help him out. I started at the fuse panel with my cheap chinese made multimeter, the meter would read voltage on some circuits and zero on others. I grabbed a screwdriver and proceeded to tighten a terminal that appeared very loose, just as soon as the screwdriver touched the terminal that my meter had said had no voltage - i received a severe shock that brought me down to my knees. After i recovered and realized i was okay i went and borrowed a much higher quality multimeter and retested the terminal voltages. Many of the circuits that had read no voltage from my el' cheapo meter were indeed live and had normal voltage. The moral to my story is that you get what you pay for when it comes to vital test equipment, and using inexpensive, poorly made equipment can cause you to have a very bad day!  I won't be testing anymore deadly circuits until i obtain a quality multimeter such as the one available from this company. My attitude has taken a shocking turn of events!

Going through the US Army's Prime Power School decades ago, we did two labs/practical exercises that really helped me understand multimeters.  One was building a multimeter from a kit - back in the Archer/Radio Shack days.  The other was a lab taking readings with that kit multimeter, an average reading meter and a true RMS meter.  I learned that cheap meters typically use a simple blocking diode, measure DC and scale for sinusoidal AC.  That means one doesn't trust a zero reading until you also reverse the leads and make another measurement - just in case.  In my current job, we work with a controller with a built-in battery charger.  One of the charger capacitors has potential on the top.  A cheap meter shows zero with the leads to cap, to chassis.  Reverse them and you get -56V.  That'll sting.  If you don't have the "better meter option", hopefully this trick will help.

Going through the US Army's Prime Power School decades ago, we did two labs/practical exercises that really helped me understand multimeters.  One was building a multimeter from a kit - back in the Archer/Radio Shack days.  The other was a lab taking readings with that kit multimeter, an average reading meter and a true RMS meter.  I learned that cheap meters typically use a simple blocking diode, measure DC and scale for sinusoidal AC.  That means one doesn't trust a zero reading until you also reverse the leads and make another measurement - just in case.  In my current job, we work with a controller with a built-in battery charger.  One of the charger capacitors has potential on the top.  A cheap meter shows zero with the leads to cap, to chassis.  Reverse them and you get -56V.  That'll sting.  If you don't have the "better meter option", hopefully this trick will help.