It was time we tested the pumps… but one thing that stumped us was the connection: it was a center ring, not the typical battery ends of + and -, and we were once again dumbfounded.
Tony tells us it is called a ‘Barrel Plug’, and a quick google search shows that its quite a ubiquitous plug design!
Justin had to educate us from scratch; linking the concepts of the cathode and anode, we learnt that the center inner ring is usually the positive end, and the outer ring, is the negatively charged end.
He let us try cool machinery to test out the different charges, and it was so fascinating to see electronics work from theory to reality.
Maybe also because we are biological science students, so the whole experience was eye-opening and enlightening, albeit a normal occurrence to the mentors in the lab.
Justin also introduced this power supply that lets you vary the voltage and current, and this may sound like common knowledge; but for someone without O level background, I learnt that V= IR… but the way I learnt it was not the conventional: as opposed to seeing it as a solution in a question paper, I saw it as a practical solution to a problem we were actually facing. And it gave a whole new dimension to V = IR.
we didnt realise we needed this, but Tony was kind enough to lend us 4, and we got about to connecting the pumps to the mosfet board and the RPi…