# resistance measurement problem with digital multimeter

I accidentally caused a short circuit with DMM common lead while measuring 220 AC voltage.

then when I tried to measure resistance it gives me a reading of 3500 ohm while there is no resistor connected and it gives me 0 ohm when I touched the test probe leads together.
my DMM is DT-9205A

• I would expect to read $0\Omega$ when the probe leads are shorted, but the open circuit reading is definitely off. – Null Nov 7 '14 at 14:28
• Maybe there was a varistor or TVS/Zener etc. diode to protect the multimeter and it has 'shuffled off this mortal coil'. – Spehro Pefhany Nov 7 '14 at 14:42

It sounds like you blew out the meter. Get a new one, and this time don't do something stupid like plugging it into the AC line on the wrong scale.

This time get a meter with a proper fuse. Good meters will simply blow a fuse when you connect the leads to the AC line on the current scale. Still, no matter how good the meter, it can't protect against all manner of cockpit errors. At some point you have to take reponsibility, which is where you are with your old meter.

You messed up. Learn from it and move on.

• "don't do something stupid like plugging it into the AC line on the wrong scale" but I didn't plug it into the wrong scale and the multimeter is working fine measuring high AC voltage. the only thing that doesn't work is resistance measuring. any way thanks for your help :) – Ali Adel Nov 7 '14 at 14:49
• @Ali: The previous incorrect use of the meter results in now seeing erroneous resistance values. – Olin Lathrop Nov 7 '14 at 18:06
• @OlinLathrop - Your comment is a little harsh. Even I, who takes very careful care of my meters with some in use for 20 years, have on occasion made an accidental meter connection when it was set on the wrong range. – Michael Karas Nov 7 '14 at 18:30
• @Michael: Sure, we've all probably done that. However that doesn't change the answer as to what happened and what to do about it. I've done stupid things with a meter too. But others also having done it doesn't make it any less stupid. – Olin Lathrop Nov 7 '14 at 21:34
• Unless this is a fancy 4½ digits meter, it's a clear throw-away. – Janka Dec 25 '19 at 4:09