High temp thermometer.

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Academic question. My most recent patent was issued in 1983, and presumably expired in 2000.

My attitude exactly. My employers saw it differently.

If you use them in the same way that their inventors did. If you had the imagination that you claim, you could see new applications for stuff that was invented to solve problems that aren't quite the same as the ones you need to solve.

-- Bill Sloman, Nijmegen

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There isn't one. It's just an interesting technical problem. The way it's working out is starting to look a bit like standards lab stuff, but that's because it looks as if we can get a remarkably low harmonic content, and we've started having to worry about all kinds of low level effects.

Notionally, the device is set up to drive a Blumlein AC bridge - the output winding will probably be a double-screened bifilar winding of the kind that Rayner and Kibble would recognise and approve of

The last time I built a circuit to do this kind of job - back in 1986

- it excited the linear variable differential transformer (LVDT) used to measure the progressively increasing mass of a single crystal of gallium arsenide (GaAs) being grown in the Metals Research GaAs Liquid- Encapsulated Czochralski (LEC) crystal puller.

-- Bill Sloman, Nijmegen

How is that wisdom workin out for you?

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No way. I've never paid a page charge in my life, and I'm not going to start now.

My h-index is two.

My most-cited paper has been cited 14 times (twice by me, which doesn't count). The next one has been cited twice, which makes my H- index 2.

Serious scientists get to around 40 - some do better.

Obviously, I'm not seriously interested in racking up more publications - it's something to do, but it's on a par with running a marathon in less than five hours (which is not one of my ambitions).

-- Bill Sloman, Nijmegen

Patents are useful in some situations, for instance:

1. Getting a good valuation for your startup company;
2. Defending yourself against predatory competitors who patent prior art things and then sue you to put you out of business (*);
3. Protecting you from folks who want to steal all your hard work in developing something really new before you have a chance to get a return from the effort.

Building a wide range of electronic gizmos for niche markets normally doesn't hit any of those things, but some other sorts of efforts commonly do, e.g. chipmaking and optical instruments.

Cheers

Phil Hobbs

(*) I've had expert witness gigs helping defend small companies from attacks of just this sort.

Rambus.

Use a cordless drill. Ken

Even the dumbest little coil winding machine has tensioning arm and a turns counter, not to mention a universal chuck to hold the coil former. People do use small lathes, but if you've got a small lathe you can probably build the tensioning arm yourself.

-- Bill Sloman, Nijmegen

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It worked out okay from time to time in the past, which is why I keep reading. Unfortunately, the stream of problems to be solved has rather dried up. The current low distortion oscillator cribs a control loop - originally intended for second-order phase-locked loops - from Floyd M. Gardner's "PhaseLock Techniques"

Unfortunately, my copy of the book is now in Sydney, so I can't give you chapter and verse. I don't think that Floyd Gardner ever patented it, and I've got no idea whether he invented the approach - it is more or less standard control theory these days.

-- Bill Sloman, Nijmegen