00:04:00 – We started the night with some history of the Cambridge Instrument Company which existed between 1881 to 1988. Founded in 1881 as The Cambridge Scientific Instrument Company by Horace Darwin [1851-1928] who was Charles Darwin’s ninth and youngest son and the company supplied laboratories at Cambridge University. There were a number of company sales resulted in the latter merged with the Swedish firm ASEA in 1988 to form ABB Group.

00:10:25 – Many ex-company employees either founded other well known companies or gained important positions in them. William T. Pye, who had joined as foreman in 1880 left in 1898 to form the W.G. Pye Instrument Company with his son, ultimately to branch out into Pye Radio Ltd.

00:11:16 – Robert William Paul (1869-1943) who had previously worked for Elliott Bros trained as a scientific instrument maker at City and Guilds College in London. In 1903 he introduced the ‘Unipivot’ galvanometer. The ‘Unipivot’ galvanometer proved to be very successful and within a few years a large number of variants and accessories for a wide range of electrical measurement were being made. Robert Paul continued to work within the enlarged organisation for the rest of his life. He also became a cinematic pioneer in the 1890s. For some interesting history on this aspect see http://www.screenonline.org.uk and http://www.thecinetourist.net/my-local-filmmaker.html

00:13:15 – Eric Balliol Moullin, [1893-1963] was a Cambridge Professor of Electrical Engineering and President of the Institution of Electrical Engineers [IEE]. He invented the first vacuum-tube voltmeter which he described in a paper to the IEE in December 1922.

00:14:30 – Went through the schematic of an earlier potentiometer including sensitive galvanometer, precision switched potentiometer, rheostat, inbuild 2 x 1.5V batteries and went through the Weston standard cell. The Cambridge Potentiometer originally created to check the accuracy of thermocouples (to 100mV) and with a Volt/Ratio box for voltages up to 500 Volts and with a variety of shunts – Current up to 1000Amps.
https://collection.powerhouse.com.au/object/319072

00:19:20 – Issue with Rheostat and possibly the standard cell – Weston 1.018?? Volts – waiting on the manual for this one then will take apart and see if we can repair.

00:19:40 – Demonstrated measurement of a very low voltage to 5-6 decimal places providing parts in a 1000 accuracy. These days it has been replaced with accurate digital multimeters

00:28:20 – Measured 0.010648V ! The 6th decimal point is an estimate but not bad for a 1950’s device!

Information sourced from the following websites:
https://www.vintage-radio.net/forum/showthread.php?t=135301
http://www.richardsradios.co.uk/cambhistory.html
https://en.wikipedia.org/wiki/Weston_cell

00:33:15 – Next showed two Morse Keys
The first key was an AWA Ship’s Key that is a fully insulated key that is beautifully made with roller bearings and made by the Marconi company MIMC.

00:35:33 – The next key was a Dept of Civil Aviation – Western Region key on a cast iron base.

00:39:00 – We then had a taster for a future DATV Night where we will feature a RADIACODE Radiation Detector – which includes a radiation detector, dosimeter and spectrometer. We will take a deep dive into the device and applications for phone and computer.

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