Basics about Balances

Weighing products used int he laboratory are typically classified as "high precision" or "precision" balances. As such, there are a number of choices - depending on the requirement in the lab. The "high precision" choices mayb include Micro Balances that are capable of determining masses in the level of 1 million parts of a gram and Semi-micro Balances that, generally, determine masses in one-hundred parts of a milligram.



Probably the two most popular types of balances that are used in the lab are the Analytical Balances and the Top Loader Balances. These are, generally referred to as "precision" balances. these products may range in capabilities from parts of milligrams to parts of grams and kilograms.




When choosing a weighing product for your lab, there are several important specifications to consider before a decision is made. For example, capacity, accuracy, and precision, reproducibility, and repeatability are all important specifications to determine for your specific requirements. A brief explanation of each of these terms follows.



Capacity

The typical mass of the sample you will be placing on the balance. Take into consideration the smallest and greatest amount you will be using with your balance.



Accuracy and Precision

Ideally your balance is both accurate and precise, with measurements all being close to and tightly clustered around the known value which is usually established by repeatedly measuring some traceable reference standards



Reproducibility

Reproducibility refers to the ability of an instrument to accurately replicate the results when done by someone else working independently.



Repeatability

Repeatability is the variation in measurement taken by a single person or balance on the same mass and under the same conditions.



These specifications will be available from the manufacturers of the balances you are considering.



There are many reputable manufacturers of weighing products. Among them are:



Mettler-Toledo

Sartorius

Ainsworth

Ohaus

Intelligent Weighing

A&D Weighing