|
Note the appearance and function of the meter.
Note and eliminate corrosion.
Zero the meter to check its operation.
Record all of the settings on the meter.
The multimeter must be on the Volts DC setting (V with dashed lines), rather than on the Volts AC setting (V~).
Why should you use Volts DC?
Answer
The V setting with the dashed lines is used to measure "volts DC", or volts in direct current. This setting measures voltages of batteries and the cells described in this module. The V~ setting is used to measure "volts AC", or volts in alternating
current, such as the electricity coming out of a wall socket. Record where each lead is connected to the meter. (VERY IMPORTANT!) By convention, the red lead is connected to the "+" terminal on the meter; and, the black lead is connected to the ground terminal (or "COM" terminal).
In the laboratory, a multimeter may display a negative cell potential. What could this mean?
Answer
The sign on the meter indicates the direction of current flow. So, a negative cell potential indicates that the leads from the meter reversed. (The positive (+) lead is connected to the anode when the meter displays a negative cell potential.) |
