Coils

1.26pm. Had an ultimately productive but at the same time frustrating session in the lab (the one that looks like it should have sewing machines in it). First we had to wind and fix a coil of wire around a ferrous rod, use cable ties to fix it into place, solder it and a 100 kilo-ohm resistor into place, then do some observations based on the inductive effect of the coil on the voltage put across it.

It took an age to get each of ours to work. Paul has far more experience soldering than me, so he finished his much sooner, but we both got strange results when each of our kits were plugged into the oscilloscope.



At first we thought that we might both have not removed enough of the insulation from the copper wire, but it turned out to be an oscilloscope problem; not a malfunction but some fiddling around with the scaling and timing. David Keen has suggested that we might even be picking up interference from one of the experimental labs on the ground floor. I'd love to have a look around that lab!

What appeared to be rampant white noise just seemed to vanish, and we found two nice traces on the screen, one displaced due to the effect of the coil. Since the displaced version of the sine wave appears to be a cosine wave, I'm fascinated as to how a LC circuit can effectively mechanically 'differentiate'.


What I think will turn out to be the case is that the displacement of the AC in the coil is proportionate to the frequency of the input AC. We'll find out this afternoon.

We stopped for lunch at 1pm, and I was ready for the break. I phoned Alan en route back to Grey, and it was good to hear his voice. He was in a taxi close to home. Would love to give him a cuddle right now.

Got to the dining hall to find a long queue. That's the only trouble with all having food at the same time. I had a small meal of scampi and chips, which was just enough to stave off any danger of hunger. I sat with Paul and Andrew, the guy who arrived early this morning. Like Paul he is from Essex, however unlike Paul he's not bad looking, balding, but incredibly hairy, practically primate-like hairy. Seems like a nice guy though.

Andrew, the latecomer, not realising that he's being photographed. Often the best photos are taken under these circumstances!

Heading back at 2pm for the afternoon shift, and I think this evening, David Keen, today's activity tutor, is doing a lecture on special relativity, which might be interesting.