dumping a lot of heat

I don't know. They are the spiral elements that saucepans are stood on to heat up when cooking.

The wire resistance element inside the spirals is embedded in some non-conductive powder (alumina?) and the outer flattened tube is steel with good high-temperature strength. This probably means the elements would have a significant inductive component.

They run dull red hot and are rated at about 1.5 to 2 kW each. There are economy types having two sections, so that only the inner one need be used for small saucepans.

I was asked the same question at my first job interview. I just said I understood valves better, which was true at the time. The Chief Engineer, who was interviewing me, then produced the circuit diagram of one of the firm's valve communications receivers and asked me to go through it and tell him what each part did.

I took one look at it and said "Yuck! It's chassis-live". My interviewer let me continue and then gave me the job. It turned out later that he hated having to make the set that way but for commercial reasons it had to work on 110v D.C. and therefore had to have the chassis connected to one pole of the mains. (The chassis was well insulated from the casing and all the outside fittings and connections.)

Throughout the entire job with that firm, I never had to design with valves - but I did ten years later when I had to make some high voltage research equipment.

There was a 1k current-limiting resistor in the HT supply (it changed colour). At least I had time to get to the 'off' switch before the valve could be seriously damaged. Luckily I was testing with reduced HT (about 100v) so the current would have been limited to about 100mA by the resistor, even if the maximum emission had been greater

I enjoy designing with them, rather than just copying well-worn circuits. There are still niches to be explored.

A few years ago I set myself the task of designing a low-noise audio preamp using a grounded-grid first stage - the result was far better than I had expected because it had repercussions on the second stage and the mixing stage which greatly improved the overload performance and the S/N ratio of the whole amplifier. If I had invented that in the 1950s, I would be a lot richer now.

I sent copies of the 'before' and 'after' circuits to a friend who is a great believer in the mystical properties of valves, but is otherwise quite sensible. It took him two days to get his mind around how the circuit actually worked.

I have never needed a touch screen. The only time I have used them is at supermarkets and that was for their convenience, not mine.

Grossly over-hyped.

My first experience with transistors was building a simple automatic parking light for a car from a circuit in a magazine. It used a photoconductive cell to switch a chain of ever-larger transistors and supply a 12v bulb. The idiot who 'designed' it had added negative feedback instead of positive feedback, so the bulb never went right out and never came full on. The heatsink got hot and it ran down the car battery in daylight.

It took a long time after that before I felt happy with transistors.

My Hallicrafters S38 was a metal box with a hot chassis inside and all the grommets had long ago failed. so I had to plug it in the right way, with unpolarized outlets. I attached a neon lamp to the top; if I touched it and it lit up, I'd switch the plug.

People used to soak in their bathtub with a radio on the table. If it fell into the water, they would die.

Life was cheap, back then.

:-)

My aunt had that radio & the same problem. I solved** it with a pair of dikes and gorilla forearms.

Ed

Oh, an electric stove heater element. At least one is usually broken.

Here's what I think we will do.

SolidWorks is great fun.