Ampere

The ampere, whose symbol is indicated with "A", is the base unit that is used to measure the intensity of the electric current.

The ampere expresses the intensity of current that passes through a conductor of any section from the charge of a coulomb in one second time.

Symbols and abbreviations:

1A = 1C / 1s = 1V / 1Ω = 1W / 1V

were: C = Coulomb, s = second, V = Volt, Ω = ohm, W = Watt.

 OHM law

At constant temperature, the potential difference (V) applied to two ends of a metal conductor is directly proportional to the intensity of the current (I) flowing through the conductor.

R = V / I (the result is in Ohm Ω)

I = V / R (the result is in Ampere)

Summary table of OHM (Ω) law

P = POWER (Watt)

P = V * I (W) if I replace V with R * I we will have P = R * I² if I replace I in the formula with V / R we will have P = V² / R

V = VOLTAGE (Volt)

V = R * I (Volt) if I replace I with P / V we would have V² = R * P = 

If I replace R with V / I in the formula, we will have that V = V / I * I = P / I since P = V * I

R = Resistance (OHM = Ω)

R = V / I if I replace V with P / I we will have R = P / I² if instead I replace I with P / V we will have R = V / P / V and finally       R = V² / P

I = Current (Ampere)

I = V / R if I replace R with V / I we will have V / V / I and since V * I = P we will have I = P / V; if I replace the V with R * I in the formula I = P / V we will have that: I² = P / R so:

 Ampere/Hour

The ampere-hour (Ah symbol) is a unit of measurement of the electric charge. It represents the amount of charge required to deliver one ampere of current for one hour.