FAQ - 1518 TC gauge - rolling your own gauge

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Richard Hull
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FAQ - 1518 TC gauge - rolling your own gauge

Post by Richard Hull » Wed May 13, 2015 6:27 pm

For those who are up to the effort, I have assembled a minimalist faq with data on making your own expanded lower end Thermocouple vacuum gauge.

Go to

http://www.ancorp.com/familyPDFs/file11 ... 52PM63.pdf

Info and pinouts on the super versatile 1518 tube is given. It has a well expanded low end when connected to the right meter.

Lesker gets $55.00 list for this tube, but the folks above get $45.00

A single 1.5 volt D cell alkaline battery with a suitable pot can set the ultra low heater current of ~15ma to set the tube up.

A good article is in the old bell jar magazine on crafting a meter from most TC gauge tubes which is most often a 10 millivolt meter of fixed impedance. (55ohm)

The article you want is found at

http://www.belljar.net/tcgauge.htm

The internet is ephemeral so print out the above article before it goes away.

The parts listed are a mere suggestion. Many modern op amps can be sustituted by the adroit electronics buff and the resistors toyed with to match the article's requirements.

The bell jar is a great vacuum website and was a great publication when Steve Hansen offered it as a quarterly.

Someone who has a minimal working relationship with electronics should find making a 1518 TC gauge a snap and with a decent parts bin, find the list price of the entire working gauge, to be the cost of the gauge tube, alone. I might even consider offering a working gauge and let others buy their own tube for it. (just thinking about it for now.) If I can't offer a working 1518 gauge without tube for under $125.00, I won't do it. I prefer analog metering to digital

e-bay is a pig in a poke buy on gauge tubes and TC gauges without a money back guarantee as most sellers are clueless, non-vacuum heads. In most cases, to be assured of a good TC setup, you need to peel off over $200.00 for the controller and another $60.00 for its mating tube.

I often pick up great TC gauge controllers, attach a good tube, clean and calibrate them and then offer them for sale for about $125.00 at my yearly HEAS event.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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