September 20, 2008


Scientific Notation

It is common to encounter very small and very large numbers in electronics. Scientific notation expresses a very large or small number as a numeral from 1 to 9 to a power of ten. For example 5000 in scientific notation is 5x103.

The exponent indicates the number of decimal places to the right or left of the decimal point in the number. If the power-of-ten exponent is positive, the decimal point is moved to the right.If the power-of-ten exponent is negative, the decimal point is moved to the left.

Figure below lists some commonly used powers of ten, both positive and negative, and the prefixes and symbols associated with them. As an example, an ampere is a large unit of current that is not often found in small-power circuits. Usually used units are the milliampere (mA) and the microampere (uA). A milliampere is equal to one-thousandth (1/1000) of an ampere or 0.001 ampere. In other words, it takes 1000 milliamperes to equal one ampere. A microampere is equal to one-millionth (1/1000000) of an ampere or 0.000001 ampere, it takes 1000000 microampere to equal one ampere.