Ampere or amp (symbol: A) is the unit of electrical current.
The Ampere unit is named after Andre-Marie Ampere, from France.
One Ampere is defined as the current that flows with electric charge of one Coulomb per second.
1 A = 1 C/s
Ampere meter or ammeter is an electrical instrument that is used to measure electrical current in amperes.
When we want to measure the electrical current on the load, the ampere-meter is connected in series to the load.
The resistance of the ampere-meter is near zero, so it will not affect the measured circuit.
| name | symbol | conversion | example |
|---|---|---|---|
| microampere (microamps) | μA | 1μA = 10-6A | I = 50μA |
| milliampere (milliamps) | mA | 1mA = 10-3A | I = 3mA |
| ampere (amps) | A |
- |
I = 10A |
| kiloampere (kiloamps) | kA | 1kA = 103A | I = 2kA |
The current I in microamperes (μA) is equal to the current I in amperes (A) divided by 1000000:
I(μA) = I(A) / 1000000
The current I in milliamperes (mA) is equal to the current I in amperes (A) divided by 1000:
I(mA) = I(A) / 1000
The current I in kiloamperes (mA) is equal to the current I in amperes (A) times 1000:
I(kA) = I(A) ⋅ 1000
The power P in watts (W) is equal to the current I in amps (A) times the voltage V in volts (V):
P(W) = I(A) ⋅ V(V)
The voltage V in volts (V) is equal to the power P in watts (W) divided by the current I in amperes (A):
V(V) = P(W) / I(A)
The voltage V in volts (V) is equal to the current I in amperes (A) times the resistance R in ohms (Ω):
V(V) = I(A) ⋅ R(Ω)
The resistance R in ohms (Ω) is equal to the voltage V in volts (V) divided by the current I in amperes (A):
R(Ω) = V(V) / I(A)
The power P in kilowatts (kW) is equal to the current I in amps (A) times the voltage V in volts (V) divided by 1000:
P(kW) = I(A) ⋅ V(V) / 1000
The apparent power S in kilovolt-amps (kVA) is equal to RMS current IRMS in amps (A), times the RMS voltage VRMS in volts (V), divided by 1000:
S(kVA) = IRMS(A) ⋅ VRMS(V) / 1000
The electric charge Q in coulombs (C) is equal to the current I in amps (A), times the time of current flow t in seconds (s):
Q(C) = I(A) ⋅ t(s)