How Do I Know The Current Strength | The Science

The Science

# How do I know the current strength

To measure the strength of an electric current in the conductor section requires special equipment - an ammeter or galvanometer (to determine the fixed and variable small electric currents).

## Instruction how to find the amperage

Step 1:

The strength of the electric current (I) - a scalar value equal to the charge (q), which flows per unit time (t) through the conductor section. According to this definition, the power of electric current can be determined from the formula I = q: t.

Step 2:

To calculate amperage refer to Ohm's law defines the relationship between the strength of the electric current, the resistance of the conductor and the voltage on the electric circuit portion. Ohm's law states that the current in the circuit section (I) is directly proportional to the voltage (U) and inversely proportional to the electrical resistance (R) of the circuit area. In other words, the strength of electric current is equal to the resistance ratio of the voltage. Thus, the strength of the electric current is calculated according to the formula I = U: R The system of international current strength is measured in amperes (A).

Step 3:

Measurement of electrical current ampermetromPodklyuchite ammeter to the area of ​​electric circuit (conductor), where you want to measure the current. In this case the correct polarity "+" connect an ammeter to the "+" current source, and it "-" connect to "-" power supply. Connect an ammeter to the circuit in series with the circuit element, by virtue of which the current to be measured.

Step 4:

To measure the small constant and variable electric currents used highly sensitive instrument - galvanometer. It is a universal device that allows to determine not only the current, and voltage. To use a galvanometer as the ammeter, connect a shunt resistor in parallel galvanometer. The plot is a circuit galvanometer connected in the same ammeter.