LEDs compare favorably with ordinary bulbs in efficiency and durability, high luminosity and lack of heating. Leaving the dimensions on overnight will not drain the battery. Thanks to all these positive aspects, many car owners want to replace their standard incandescent bulbs with LEDs.
Necessary
- - LED or several LEDs;
- - resistor of constant or variable resistance;
- - dviver LM317;
- - multimeter
Instructions
Step 1
First of all, tune in to neat and attentive work. Any wrong actions can lead to damage to the car's electrical equipment. Remember the main characteristics of LEDs: the supply voltage of yellow and red elements is usually 2-2.5 V, blue, green and white - 3-3.8 V. The current of a low-power element is 20 mA, a powerful one is 350 mA.
Step 2
Remember the technical features of LEDs: the ability to illuminate the space around you depends on the type of lens installed, which can provide a narrow or wide beam of light. The plus of an LED is called the anode, and the minus is called the cathode. Comparing the voltage of the car's on-board network and the voltage of the LED, make sure that simply plugging it into the on-board network can burn the element.
Step 3
To connect the LEDs, assemble a simple homemade cluster of several elements and a resistor. To do this, count the required number of LEDs by dividing the voltage of the on-board network (12-14 V) by the voltage of one element. Link the required amount together in sequence, i.e. connect the plus of one with the minus of the other, and so on to the end of the chain.
Step 4
Connect the remaining two extreme terminals to the on-board network through a resistor that suppresses excess voltage (100-150 Ohm; 0.5 W). Such a cluster will have an unpleasant effect: the intensity of the glow will change depending on the engine speed.
Step 5
Using this method, connect any number of LEDs, collecting them in clusters (usually 3 pcs.) With a resistor and connecting them in parallel. At the same time, connect the clusters in a parallel method (plus and minus). To roughly estimate the value of the resistor, use the rule: 1 LED needs a 500 Ohm resistor, two - 300 Ohm, three - 150 Ohm.
Step 6
Calculate resistor values more accurately using Ohm's Law. To do this, divide the voltage to be extinguished by the current to be obtained. Measure the voltage exactly at the point at which you will connect the element with a multimeter. Subtract the LED voltage or the summed voltage of multiple diodes from this value. Get the magnitude of the voltage to be repaid. Divide it by the power of the diode in amperes. Remember to convert milliamps, which represent cell current, to amperes.
Step 7
To check, measure the amperage between the resistor and diode. In this case, take into account the spread in the parameters of the resistor and diode, due to which the current strength can vary up to 5 mA in either direction. If the obtained value is higher than the calculated one, the LED will shine brighter, but its service life will be reduced. Use a variable resistor to adjust the desired current value.
Step 8
Add a voltage regulator to the circuit. This will allow the LED or cluster to glow at a brightness independent of the engine speed. The simplest and most reliable stabilizer is a circuit based on the LM317 microcircuit. Purchase one in a store and connect it with one end terminal to an LED or cluster, and the other to the on-board network. Connect the resistor with one lead to the middle lead of the LM317, the other to the cluster (LED). When installing, attach the LM317 microcircuit only to an insulating gasket.
