How to assemble a 12 V voltage regulator for cars with your own hands
When using as a system of lighting for the car LEDs – in the scheme must be – 12 volt voltage regulator, which is quite possible to assemble with their own hands.
Consider why you need a special regulator of output parameters of electric current for additional lighting in the car, as well as how to independently make it in variants – on the Krene, with two transistors, on the operational amplifier and on a switching microcircuit.
What stabilizers do and why you need them
LEDs in the form of individual lamps or ice strips provide a wide opportunity to create both the main lighting and additional auto illumination. However, the parameters of the current on-board electrical network are far from stable and constantly changing. Therefore, and it is necessary to install a 12 volt voltage stabilizer in the circuit. Its main functions are:
- Elimination of sharp fluctuations in the parameters of electric current in the car network.
- Protection of electrical equipment from both lack and excess voltage. Fluctuations can reach several volts, which is already destructive for any LEDs.
- Protection of particularly sensitive components of devices from network interruptions.
- Preventing rapid degradation of the crystals in LEDs, their fading and flickering, preserving the declared service life of the manufacturer.
A simple or more advanced 12 volt voltage regulator for cars with the specified output parameters of electric current can be created with your own hands. The total cost of its components will be ten times less than the cost of purchased analog, with the correctness of the circuit assembly will ensure reliability no less than the factory models.
Diagrams of stabilizers and current regulators
There are at least four options for making 12 volt voltage stabilizers for cars with their own hands:
- On a krank.
- On a pair of transistors.
- On the operational amplifier.
- On a chip of a pulse stabilizer.
Let’s analyze what the main features of each of the considered modifications have.
On a Kreneke
To assemble your own hands the simplest stabilizer for LEDs for cars for 12 volts will be required:
- LM317 chip or KREN8B (more accurately KR142EN8B), or KIA7812A.
- A 120 ohm resistor.
- A printed board or perforated panel.
The pictures show the location of the main components of the circuit of the simplest stabilizer for LEDs in the car:
The second circuit uses a 1n4007 rectifier diode at the input from the battery.
With two transistors
One of the most popular automotive voltage regulators for 12 volt LEDs, which is also assembled with our own hands, today is a scheme on two transistors.
The alternating voltage of 12 volts goes to the diode bridge VD1 – VD4, is rectified and, passing through the filters C1-C2, is smoothed. Then the current goes to the parametric stabilizer VD1 and passes to the resistor R2. Then from its slider it is passed to the key of the compound transistor VT1 VT2. Its openness level is determined by the state of the slider of variable resistor R2 – in the lower state of the regulator the transistors are closed and no voltage is applied to the load, and in the upper state of the regulator R2 it is maximum and the transistors are fully open, the voltage is applied to the load.
Interesting! The device allows you to set the parameters of electric current at the output within the range – from 0 to 12 volts and up to 3 amps. When assembling the circuit consider that the rectifier diode bridge VD1 – VD4 and transistor VT2 can significantly overheat. Therefore they should be mounted on a radiator with a usable area of about 260-270 cm². Besides the diodes themselves should be able to withstand a current of not less than 10 amps (which corresponds to D245-D247).
The given model of voltage regulator for cars is most often used for daytime running lights based on LEDs and allows successfully adjusting the parameters of on-board current to the characteristics of the lighting device.
On the operational amplifier
12 volt voltage regulator for LEDs in the car, it makes sense to make their own hands when there is a need for its work in an extended range of operating parameters. Below is a diagram of such a device. Its main feature is that the amplifier itself is included in the feedback circuit and fed directly from the output of the stabilizer. The device has a stabilization factor of about 1000, with an output resistance of less than 10 ohms and an efficiency of about 50%. Load current at nominal – not less than 200 μA, with a ripple voltage at the output in double amplitude – less than 60 μV.
Among the main features of its operation are:
- Operating temperature range -20 to +60 degrees.
- Thermal drift of output voltage – less than 0,05%.
- Possibility to increase voltage at the output up to 27-30 volts.
To solve the latter problem, you need to install a 200 ohm resistor between pins “7” and “+25”. Transistor cascade VT1 acts as a dynamic load for VT4 and thus increases the overall gain. Transistor P702A can be replaced with analogs P702 or KT805, and KT603G with P308 or P309, respectively, as well as KT201B and KT203B with MP103 or MP106.
On the chip of the pulse voltage regulator
When from the voltage regulator for the car requires a high efficiency, it is better to collect their own hands the device with the use of pulsed components. The most common is the scheme below MAX771 (or analogues 770, 772).
The pulse type regulator has an output power of 15 watts. The circuit elements R1 and R2 separate the voltage reading at the output points. In the case when it becomes higher than the base, the pulse rectifiers simply reduce its output value. In the opposite case, the device will, on the contrary, increase this parameter at the output.
Mounting and installing with your own hands a switching voltage regulator for LEDs in the car is reasonable when its value exceeds 16 volts. If there is an increased load drop, an operational amplifier should be introduced into the circuit.
Recommendation! When choosing a ready-made voltage regulator for LEDs in the car, it is necessary to proceed from the fact that the lighting system is provided with a current with stable values. For most lighting devices this is 12 volts. If the devices are made by hand, before introducing them into the circuit, you need to measure their output characteristics with a multimeter.
12 volt voltage stabilizer is installed in the electrical circuit of the car, when it is necessary to maintain the performance of LEDs and prevent them from the harmful effects of variable parameters of the on-board current. The device can be purchased or with sufficient experience in radio engineering to assemble their own hands. There are four popular options for self-assembly:
- On a krank.
- With two transistors.
- With the help of an operational amplifier.
- With the use of a pulse chip.
Each of these has its own peculiarities. When selecting components and when assembling with your own hands, you must strictly follow the suggested circuit diagram.
If you want to add your own information to the above schemes, or if you have your own version of making your own 12 volt stabilizer for LEDs in the car, be sure to share it in the comments.
Making a current regulator for LEDs with their own hands
If you decide to re-equip your car for LED lighting, you will need at least a current regulator on lm317 for LEDs. To assemble an elementary stabilizer is not difficult at all, but to avoid deplorable blunders, even with such a simple task does not hurt a minimum literacy. Many people who are not connected with radio electronics often confuse such concepts as a current regulator and a voltage regulator.
It’s easy on the simple. Amperage, voltage, and their stabilization
Voltage determines how fast electrons move through a conductor. Many hardcore computer overclockers increase the voltage of the CPU core to make it run faster.
Current strength is the density of electrons moving inside an electrical conductor. This parameter is extremely important for radio elements working on the principle of thermoelectronic secondary emission, in particular, light sources. If the cross-sectional area of the conductor is not able to allow the flow of electrons, the excess current begins to be released in the form of heat, causing significant overheating of the part.
For a better understanding of the process, let’s analyze the plasma arc (it is the basis for the electrical ignition of gas stoves and boilers). At very high voltages, the speed of free electrons is so high that they can easily “fly” the distance between the electrodes, forming a plasma bridge.
And this is the electric heater. As the electrons pass through it, they transfer their energy to the heating element. The higher the current, the denser the flow of electrons, the more the thermocouple heats up.
Why Current and Voltage Stabilization is Needed
Every electronic component, be it a light bulb or a computer central processor, requires a finely tuned amount of electrons flowing through its conductors for optimal performance.
Since our article is about a stabilizer for LEDs, let’s talk about them.
For all their advantages, LEDs have one disadvantage – high sensitivity to power parameters. Even a moderate excess of power and voltage can lead to the burnout of the light-emitting material and the failure of the diode.
It is now very fashionable to redesign the car lighting system with LED lighting. Their color temperature is much closer to natural light than xenon and incandescent lamps, which is much less tiring for the driver on long trips.
However, this solution requires a special technical approach. Nominal current supply car LED diode – 0.1-0.15 mA, and the starting battery – hundreds of amps. This is enough to burn out a lot of expensive lighting elements. To avoid this use a 12 volt stabilizer for LEDs in the car.
Amperage in the car network is constantly changing. For example, a car air conditioner “eats” up to 30 amps, when you turn it off, the electrons “allocated” for its work will not go back to the generator and the battery, and will be redistributed among the other electrical appliances. If the incandescent bulb designed for 1-3 A additional 300 mA will not play a role, the diode with a supply current of 150 mA several such jumps can be fatal.
In order to guarantee the long life of automotive LEDs a lm317 current regulator for high-power LEDs is used.
Types of regulators
According to the method of current limitation there are two types of devices:
Linear stabilizer works on the principle of a voltage divider. It releases the current of a given parameter, dissipating the excess in the form of heat. The principle of operation of such a device can be compared to a watering can equipped with an additional drainage hole.
- reasonable price;
- the simple scheme of installation;
- it is easy to assemble with your own hands.
Disadvantage – because of the heat is poorly adapted to work with heavy loads.
Pulse stabilizer as a vegetable slicer through a special cascade slices the incoming current, giving a strictly dosed rate.
- designed for heavy loads;
- does not get warm during operation.
- requires a power supply for its own operation;
- generates electromagnetic radiation;
- relatively high price;
- difficult for self-manufacturing.
Given the small current in automotive LEDs, you can build a simple stabilizer for LEDs with your own hands. The most affordable and simple driver of LED lamps and strips are assembled on a chip lm317.
A brief description of the lm317
Radio-electronic module LM317 is a microcircuit used in current and voltage stabilization circuits.
- A voltage stabilization range of 1.7V to 37V will provide stable LED brightness independent of motor speed;
- Supporting an output current of up to 1.5A will allow several photo-emitters to be connected;
- High stability allows only 0.1% of nominal output to fluctuate;
- It has built-in current limiting protection and overtemperature shutdown stage;
- The chip body is ground, so when mounted with a self-tapping screw to the car body, the number of mounting wires is reduced.
- Voltage and current regulator for LEDs in household conditions (including LED strips);
- Voltage and current stabilizer for LEDs in the car;
Diagrams of current regulators for LEDs
The simplest stabilizer circuit
The simplest 12 volt voltage regulator can be assembled using this circuit. Resistor R1 limits the output current, R2 the output voltage. The capacitors used in this circuit reduce voltage ripple and increase operating stability.
The needs of the motorist will be satisfied by the simplest stabilization mechanism, because the supply voltage in the car mains is quite stable.
To make a stabilizer for diodes in the car will need:
- A lm317 chip;
- Resistor as a current regulator for LEDs;
- Soldering and mounting tools.
Assemble according to the above diagram
Calculation of a resistor for an LED driver
The power and resistance of the resistor are calculated based on the current of the power supply and the current required by the LEDs. For a 150mA car LED, the resistance of the resistor should be 10-15 Ohms, and the estimated power of 0.2-0.3W.
See the video for how to assemble it with your own hands:
The affordability and simplicity of the driver design on the lm317 chip allows you to painlessly retrofit the electric lighting systems of any car.