Effect of the power on the LED Headlamps

Power factor is an important parameter of led lamps, no matter rechargeable LED lamps or Dry LED lamps. So let's further understand what power factor is.

1、Power
The power factor characterizes the ability of the LED headlamp to output the active power. Power is a measure of the transmission rate of energy, and in DC circuits it is the product of voltage V and current A.In the AC system, it is more complex: some AC current circulates in the load, which is called reactance current or harmonic current, which makes the apparent power (voltage Volt by current Amps) greater than the actual power. The difference between apparent power and actual power leads to the power factor, and the power factor is equal to the ratio of actual power to apparent power. So the actual power in the AC system is equal to the dependent power times the power factor.
That is: power factor = actual power / apparent power. Only the power factor of linear load such as electric heater and light bulb is 1. The difference between the actual power and the apparent power of many equipment is very small and negligible, while the difference between capacitive equipment such as lamps is very large and important.

2、Apparent power
Active power: the product of AC voltage and AC current. With the formula as: S=UI. Where S is rated output power in VA (volt-ampere); U is rated output voltage in V, such as 220V, 380V, etc.; I is rated output current in A. The apparent power consists of two parts: active power (P) and reactive power (Q). Active power refers to the part of the work done directly. For example, the light up, the motor rotation, the electronic circuit working. Because this power has become heat, can be directly felt by people, so some people have an illusion, that is, the active power as the apparent power, who knows the active power is only a part of
The apparent power, with the formula: P = Scos θ = UIcosθ =UIF. Where P is the active power in W (watts); F=cos θ is called the power factor, and θ is the phase difference of different voltage currents at a nonlinear load. Reactive power is the part of the power stored in the circuit but not directly worked, expressed by the formula: Q = Ssin θ = UIsinθ. Where Q is the reactive power in var (lack).

For Led headlamps and all other electronic circuits that work on DC voltage, it is impossible to work without power.