Last week in robotics, I looked more into Ohm’s Law and Kirchhoff’s Law in some basic circuits. Ohm’s Law made sense at first, and when I did the maths to find amperage and voltage throughout a circuit, I got results that seemed correct. When having two 1k resistors in succession, the final voltage added up to be the same as the initial voltage, as it was supposed to. This indicated to me that the parts in between was correct. Upon applying this maths to a real circuit, and after learning how a multimeter works, we tested to see the power at different points. The results from the multimeter lined up with the theoretical results from the maths. At this point I thought I had a solid understanding of the basics of Ohm’s Law.

We then tried including Kirchhoff’s Law into this by making a circuit which split into two different parts, running different levels of resistance, 1k and 220r, parallel to one another. This type of circuit was much harder than the previous.

Diagram of circuit running parallel resistors (from owlcation.com/stem/Resistors-in-Series-and-Parallel-Formula-Derivation)

We initially thought that we would use Kirchhoff’s Law to split the current, then use Ohm’s Law to find the level after resistance was applied, and then use Kirchhoff’s Law once more to join the two currents at the end. This, however, was not how it was meant to be done, as we worked out at the end after we calculated the final voltage to be -13 (roughly), which we figured wasn’t supposed to be the answer.

It turns out we didn’t understand Kirchhoff’s Law when in conjunction with Ohm’s Law, as there is a different method by using the inverse of the values. After we redid the maths with the newly found method, we got our desired end result of 5 volts. We then decided to once again build the circuit, however more problems arose at this point. Once the circuit was made, we got the multimeter to see if the maths was correct. We found that there was initially 5 Volts, as expected, but straight after the resistors we found there was no power whatsoever. We wanted to test at what point there was no longer power, so we put some LEDs on the board and tried to wire them in. We didn’t double check that everything was in the right spot, and when it was plugged in there was a pop followed by a smokey smell. Luckily only the LED was damaged, and not the board of computer. Since this we have not yet reattempted to see where we are losing power, as that will come in the following weeks.