Weighing scale
The balance (also balance scale, beam balance and laboratory balance) was the first mass measuring instrument invented. In its traditional form, it consists of a pivoted horizontal lever with arms of equal lengththe beamand a weighing pan suspended from each arm (hence the plural name ""scales" for a weighing instrument). The unknown mass is placed in one pan and standard masses are added to the other pan until the beam is as close to equilibrium as possible. In precision balances, a more accurate determination of the mass is given by the position of a sliding mass moved along a graduated scale. Technically, a balance compares weight rather than mass, but, in a given gravitational field (such as Earth's gravity), the weight of an object is proportional to its mass, so the standard masses used with balances are usually labeled in units of mass (e.g. g or kg).
Chart recorder
One of the first digital units was designed by William (Bill) C. McElroy jr working for Dohrman Instrument Company in Santa Clara, California. Up until this unit, most chart recorders were rack mounted and had one speed and one sensitivity range. Mr. McElroy's design was an instant loading paper roll 'table-top' unit using an Integrated Chopper Circuit for signal conversion. The unit had plug in circuit boards, plug in single or multi-range modules and plug in single or multi-speed modules. The recorder's sensitivity was 1 microvolt to 100 volts full-scale, which at the time was an industry first. Mr. McElroy also aided in the design and build of the Gas Chromatograph used for analysing dirt and rock samples from the 1969 moon landing.