Intro

Before modern quantum voltage standards and lesser budget-friendly solid-state zeners we had voltage defined from arrays of chemical hazmat-grade cells. They were quite fragile and difficult to operate. In this short post we can look at the enclosure used by Mallory for such array, originally intended for 10 cells for larger EMF and various laboratory practical use cases.

Mallory Battery Company was a well known manufacturer from 1916 of the various chemical cells, capacitors and electronic devices. In 1978 company was acquired by Dart Industries and now known as Duracell with HQ in Chicago, Illinois, USA. Duracell still make batteries today.

Heavy-duty metal box has nice deep emboss letters, Mallory logo and mysterious “Voltage Reference Battery” naming with part-number 303113.

Number of patents are embossed on the back of the enclosure. They are quite interesting to educational and historical purpose:

• US2422045A: Alkaline dry cell, 1945
• US2542575A: Alkaline dry cell, 1946
• US2636062: Electrochemical cell and selfventing enclosure therefor, 1949
• US2712565: Electrochemical cell, 1953
• USRE23427E: Primary cell with permanganate, 1951

These patents from co-founder of Mallory Samuel Ruben and others describe various aspects of chemical references used back in late 1940’s and 1950’s.

But in my case here this is just a metal thick box with posts panel, no magical chemical guts or contents were present inside.

Posts are nickel or tin plated, so not super-low thermal.

Let’s take a look in supplied manual booklet:

Calibration values were written right into the calibration chart available in the book. Stamps at the bottom suggest that calibration was done at three time periods: June 14, 1965, September 30, 1965 and February 14, 1966.
We can even see some of the values assigned to each cell point:

Nominal Point	3 months age, June 14, 1965	Nominal	9 months age, September 30, 1965	Nominal	15 months age, February 14, 1966
1.355 V	1.35408 V	1.352 V	1.35173 V	1.347 V	1.34926 V
2.710 V	2.70880 V	2.704 V	2.70363 V	2.694 V	2.69926 V
4.065 V	4.06264 V	4.056 V	4.05603 V	4.041 V	4.04926 V
5.420 V	4.51690 V	5.408 V	5.40847 V	5.388 V	5.39996 V
6.775 V	6.77143 V	6.760 V	6.???23 V	6.735 V	6.75086 V
8.130 V	8.12913 V	8.112 V	8.11336 V	8.082 V	8.10120 V
9.485 V	9.47943 V	9.464 V	9.46515 V	9.429 V	9.45091 V
10.84 V	10.83396 V	10.816 V	10.81792 V	10.792 V	10.80156 V

Pretty cool historical record. They already had 6½-digits measurement capability in 1965, sixty years ago, way before first Intel 8008 8-bit processor.

There you have it, a little piece of history. What should we do with it next? Make a custom PCB with some ADR1001 chips and lithium battery to generate modern 10 V box? :)

Discussion is very welcome at our own IRC chat server: xdevs.com (port 6010, channel: #xDevs.com) or by contacting us directly.

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