Audio Basis - articles about audio
Electrical power is electrical energy per second. Read below how power, energy, voltage, current, resistance are related. Keep reading...
In electrical devices, the energy is converted to other types of energy: mechanical, light, others. The rest of the electrical energy is converted to thermal energy via resistance. Practically, a significant part of the electrical energy is wasted on heat.
Electrical energy in many cases is converted to the thermal one
When we reviewed voltage we discuss that voltage is potential, which can cause the movement of charged particles (electrons).
The electric energy, that moves through a wire (conductor), generates magnetic energy.
But the electric energy will be consumed, if a closed wire loop is placed in the magnetic field of the conductor. As example, a metal ring is placed about this wire.
Electrical energy converted to magnetic energy
The current in the ring flow inside the metal ring and energy is consumed from the electric wire via the magnetic field.
Consuming the electrical energy (and current respectively) in the electric wire is increased. More current - more energy is lost at the electric wire for heat.
The energy of the audio signal is considered as a square of signal shape.
Graphical presentation of electrical energy
Power is called P.
Energy is called E.
Power is the energy per second.
P = E / t, where
t is time.
Power is calculated in several ways:
P = U * I
P = U2 / R
P = I2 * R,
where
U is voltage,
I is current,
R is resistance.
DIN POWER is a value of sine power:
RMS (Rated Maximum Sinusoidal) is maximal sine audio power when audio unit is capable to work:
PMPO (Peak Music Power Output) is maximum sine audio power when an audio unit is capable to work:
DIN POWER < RMS < PMPO
There is no universal method to convert PMPO to RMS safely.
Theoretically, if you know exactly PMPO's measurement conditions for a given device, you can calculate PMPO energy and calculate the power with the same energy but during 1 hour. It will be like RMS.
But, for calculated RMS, the cooling abilities of the device and its resistance to the temperature may cause damage issues. And actual RMS should be lesser or, maybe, higher.
Audiophile Inventory's developer
Electrical enegry is measured in Joule or Watt × second/Watt × hour.
< Read about electrical resistance
December 9, 2022 updated | since September 7, 2017
