Han Wang
TRITA LWR Degree Project 11:29
Figure 8. Multi-meter to test voltage data LA-110 is an analytical balance with high performance. The display update only requires 0.1 to 0.4 second and also with selectable weighing units (g, kg, GN, mg, ct, lb, oz, thl, tlt, dwt etc.). The maximum capacity is 110 g, which means it is only for small scale experiment usage. The readability and reproducibility specifications are 0.0001 g and ±0.0001 g, respectively. LA-110 is frequently used in the experiment (Figure 7). It was mainly responsible for weighing chemical compounds in addition to be added to MFC/MDC as nutrient solutions. In this whole experiment, chemical compounds includes sugar, potassium chloride, sodium chloride, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium acetate, ammonium chloride, magnesium chloride hexahydrate and calcium chloride hexahydrate etc. 4.2.2. Multimeter Multimeter is a hand-held electronic measuring device that can be applied in many circumstances. It has lots of basic functions such as voltage, current and resistance measurement. Usually it provides measurement function of both alternating current/voltage and direct current/voltage. In this experiment, all of the measurements are set as direct current/voltage. BS1901W series has been chosen as the voltage measurement device (Figure 8). It is a 3 1/2 Digits all-ranges protection meter with battery test. The measuring range is between 200 mV to 600 V and DC current from 20 mA to 200 mA. Due to limitation of present lab conditions (no data logger is available), it is possible to record voltage data by connecting multimeter to the circuit 24 hours together with video monitoring (for instance, open video monitoring software before the lab is closed, and on return the next morning, voltage data at every moment can be seen from the software “YouCam”). 4.2.3. Conductivity meter Conductivity is important in MFC/MDC test. Previous research (Cao, 2009) has been shown that with a higher conductivity, the MFC/MDC performs more efficient and gives higher maximum voltage output. Conductivity meter is such a device that can measure conductivity in solutions. It is widely known that salt content reflects the 14