The scope of LEDs for today is huge and constantly expanding. But not so long ago this device could be found only in the indication circuits. It was not designed for heavy workload. Developed more and more powerful devices that can work in the field of lighting. There were spotlights and lamps based on high-power LEDs. They are used in the automotive industry, participate in road lighting and regulate traffic with the help of powerful traffic lights. There were household appliances, which are a good analogue of existing lighting devices. LED lights are beginning to appear in our apartments, on staircases and in offices.
Unusual properties of LEDs have long attracted the attention of designers. In the automotive industry , parking lights and stop lamps are used on the basis of these devices. One of the directions in the design of the car is the replacement of obsolete lamps inside the interior with LEDs. Also they are widely used for indication on the instrument panel and interior lighting. The smooth inclusion of LEDs - this is one of the promising solutions in tuning the car. For example, the light in the cabin can glow or fade, respectively, when opening or closing the doors. Or the illumination on the control devices can smoothly turn on / off when activating any device, for example, parking lights.
It is not difficult to organize a smooth switching on of the LEDs; for this it is necessary to collect a small circuit. If the power consumption of the load is low, then you can use a simple polar capacitor, soldering it parallel to the lighting device. Do not forget about the polarity (the positive terminal of the capacitor must be connected to the anode wire of the LED). Negative, respectively, with the cathode. The capacitor may explode if improperly connected! Also pay attention to the maximum voltage at which this circuit operates. It must not exceed the permissible operating voltage of the capacitor.
Having correctly collected the circuit, you can immediately see the smooth switching on of the LEDs. Capacitor capacitance is not recommended to increase by more than 2200 MkF, as exceeding this value will lead to a rapid deterioration of switching equipment. The fact is that when the voltage is applied to the circuit, the capacity begins to be charged. At the first time, there is a decent starting current, which can damage the relay contacts. The above capacitance of the capacitor allows to ensure a smooth switching on of the LEDs with a time delay of up to 3-5 seconds. This happens by exponential law, that is, initially you get about 20-40 percent of the lighting in the cabin. For a few seconds after this, the LEDs are switched on smoothly to the nominal mode of their operation.
To work with more powerful lighting devices, one capacitor is not enough. Smooth inclusion of such devices is organized using circuits where the current consumed by the LEDs is controlled by the output stage, assembled, for example, on transistors. Time delay in this case is realized by various electronic circuits.