#8 To Be An Engineer

If you are an engineer, you like strolling around for hours in stores selling technology. The other day, I found very convenient heat retainers to keep the food warm at the dinner table. When I came home, I realized that this model was designed to warm up quickly, pull out the electricity cable, and put the retainer at the table without electricity feed. Very warm in the beginning and promptly getting too cold. Not useful for me!

The “only” problem was that they consumed 800 Watt, which was far too much for continuous operation. An average person had maybe packed them back in the original box and left them in the store. But apart from the wrong warming function, I found them stylish, and they had the correct size.

Hmmm ! Probably they contained some simple resistive heating unit, without electronics and other sophistications. Then, the idea struck me, what if connecting them in series. Hmmm ! The voltage would be divided between the two retainers, half the voltage over each unit. The total resistance for the retainers connected in series would be double, making the current decrease to half. The power is the voltage times the current, and if both of them get halved, the power would be a quarter, making each retainer go from 800 Watts to 200 Watts. Hmmm ! Wouldn’t that be perfect for continuous operation on the dinner table?

So, I went back to the store again and searched out components to build a “power splitter” box, see the picture to the left. These are common, cheap things, but one must be aware that they fit together. It was also important to find two separate power plugs, which you could be able to connect in series. It took only an hour or so to assemble, and the box was connected to the retainers for a test; see the right picture. My engineering intuition was working perfectly; the retainers got perfectly warm – you could hardly hold your hand on them for a long time, but they were not dangerously hot for the food and the table.

My sensmoral is simple – I hardly need these retainers and the splitter box, but they were impossible not to construct.

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