Practical 8: Electricity 2
Practical 8
Week 13
Teammates Present: Nelly and Trumann
Written By Trumann
The first thing done this session was to find out the voltage and current of the solar panel using a multimeter, crocodile clips, a usb wire with exposed wires, a led bulb and batteries under the afternoon sun. The led was to be used as an indicator whether a current was present. The usb wire was plugged into the solar panel as a way to receive power from it. The batteries were wired to test if the led was working first. The led bulbs did not light up when wired to the batteries or the solar panel even though the multimeter measured a current flowing. The crocodile clips were then attached to the exposed wires but the other end of the clips were not connected. The current and voltage was then measured at the point where the crocodile clips and wires met. A constant 5.15 V and varying range of 1.2 A to 0.2 A was measured. The A varied due to the amount of sunlight the solar panel was exposed to.
Solar panel measurement setup
There was a concern whether the readings recorded where valid was it was unknown whether the circuit was in series or parallel. The team will investigate it further in the next session.
In the next part of the session, the electrolysis set was set up and the 1 M KOH solution was prepared. The measurement method of the prototype is by electrolyte displacement which means that when gas is produced in the air tight container, the electrolyte will be displaced through the pipe and into a beaker where the volume is measured to determine the amount of gas produced. This type of measurement has its benefits and drawbacks and the team will further test and finalize the preferred way of measuring.
Electrolysis setup
Once the clips were attached to the electrodes, an issue came up where there is no current flowing in the system. The team checked every part of the setup to find out what was the issue. Out of the blue, there seemed to be a flow of current. Results were then obtained but was stopped after 30 mins as one of the clips was heating up excessively and broke apart. This could be due to bad contact between the clip and the metal connectors of the power supply.
Burnt crocodile clip
Wire made for power supply
The new wire for this power supply was used in place and the set up worked fine. Results were obtained and the graph below was plotted with the results.
Graph of mA vs V
From this graph, a linear relationship between mA and V is observed. The lowest voltage where electrolysis starts is at 1.9 mA at 0 A.