Early History of Multimeters
The thing which we called a digital multimeter today is not a fortune discovery or something devised in laboratories in 10, 20 years. It’s actually transformed with time, improved, reshaped, and re discovered. Multimeters’ history starts from back in the early 19th century when the first device was invented that can be called the predecessor of multimeters, it was an early form of what we say today as a galvanometer.
The downside of this device was its heavier and bulky design, it was not such a tool weighed under 1 or two pounds which you can carry with you in field works. It had a pointer to detect electrical current only. So practically it was only for laboratory works, not suitable for fields.
With time engineers and scientists managed to make separate devices for voltage and resistance calculations but didn’t succeed to combine them in a single tool like today’s top digital multimeter. This thing irritated Donald Macadie, a British post office engineer who was tired of moving with a bunch of tools from one site to other.
He wanted to solve this issue to have one tool that can find current, voltage, resistance, and continuity. With repetitive efforts, he was successful in inventing a device which we can call Avometer or a VOM. Still, it was not much lighter in weight, with time engineers tried to shrunk its design and lower its weight. In the 1930’s they were successfully made a device even with more features and ideal design for outdoor works.
With all these advancements there was one thing lacking in these avometers, which was ac current , voltage, and ohms measurements. Thanks to Westinghouse, they introduced first general avometer after the invention of the copper oxide instrument rectifier, which can be used both for ac and dc systems. This time this earlier form of a voltmeter also came with improved range and more number of features.
The first Digital Voltmeter
In 1953 NLS produced its first digital display voltmeter, but it was still heavier in weight with a design that can only be used in laboratories. Somehow we can say it a first multimeter with a digital display screen. NLS continuously works for decreasing its size and enhance capacity and number of functions, so they came back with a more efficient design of NLS LM-4 digital voltmeter. It was the smallest multimeter of its time which was quite feasible for outdoor use.
First Handheld Digital Multimeter
The mighty fluke 8020A was the very first device that could be considered relatively same as multimeters we use today. Interestingly it was built with the capacity to test voltage with range 750AC and 1000 DC. There was a more advanced and simple interface having easy to understand meter symbols and buttons. The current range was 2000 milli amps and its resistance capacity was up to 20 mega ohms. Imagine in 1977, that was a gift for electricians and contractors because it eliminated need for laboratory type instruments in fieldwork.
After fluke, morris and hioki also introduced their first digital multimeters in market in the late 1970’s.It was all possible when semiconductor technology become cheaper. Before it, semiconductors can only be produced through some expensive equipment like tunneling amplifiers or molecular beam epitaxy (MBE).