Resistance changes from zero to the nominal value of Euro and no transitions or jitter phenomenon indicates normal potentiometer

First measure the resistance value between two fixed ends is normal, if Europe is infinite or zero or nominal power transformers the larger, exceeding the permissible limit, are described corrupted; resistor resistance to normal, then a multimeter table pen potentiometer wiper, another table pen potentiometer (variable resistor) either a fixed end, slowly rotating mandrel, observe whether smoothly changing hands, mcb circuit breaker one end to the other end of the rotation, the resistance from zero Europe changes to the nominal value (or vice versa), and no transitions or jitter Electric energy meter, then the potentiometer is normal, if there is in the process of rotating hopping or jitter phenomenon, indicating that the sliding resistance of body contact points are bad.