Page 1 of 1

FAQ - 1518 TC gauge - rolling your own gauge

Posted: Wed May 13, 2015 6:27 pm
by Richard Hull
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 ... 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

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