| 摘要 |
An apparatus and method is provided for measuring the continuity and resistance of electric circuits, particularly electric wire circuits used in blasting, in the presence of spurious voltages due to galvanic currents. A constant current from a cell is passed through the electric circuit to be tested and through a reference resistor where the voltages are measured to derive the resistance of the circuit. The measured voltages are sensed with a converter converted to a resistance measurement and displayed. The presence of spurious voltages is compensated for by connecting a galvanic current storage capacitor in the circuit, passing a reference current through the reference resistor and the circuit and comparing the voltage across the reference resistor with the voltage across the circuit and storage capacitor to derive a resistance reading. The reading is converted to a digital display. The method and apparatus provides a quick, convenient means of testing blasting circuit continuity in the field in the presence of stray current caused by in-earth galvanic action. |
