Speed regulator for 12V motor or dimmer of lamps

How to make a dimmer for 12 and 220 V with their own hands?

To adjust the intensity of lighting, you can use special switches – dimmers. They allow you to change the strength of the light flux from maximum to complete shutdown. However, factory dimmers have a number of disadvantages, among which is quite high cost. To solve the problem, you can make a dimmer with your own hands for 12 and 220 volts, depending on the type of circuits for which you are going to use it.

What will be needed for work?

Dimmer is a dimmer that allows you to turn a knob or press a key to change the intensity of light in a room.

By the type of dimmer control, they come in:

  • resistive;
  • transformer;
  • semiconductor.

The first option is the easiest, but it can not be called economical, because reducing the brightness of the glow does not change the power of the load. The other two are much more efficient, but have a more complex design. Depending on the principle of operation and will depend on what parts include a dimmer. To avoid being distracted from the work, it is better to have everything you need in advance.

For the following examples you will need the following electronic elements:

    – Is a key in a circuit, used to open or close a section of the circuit from the flow of electric current. It is used in circuits with a supply voltage of 220V and has three terminals – two power terminals and one control terminal. – It is also mounted as a key and is driven to the steady state required for circuit operation.
  • Microcircuit – a more complex electronic circuit element with its own logic and control features.
  • Dinistor – also a semiconductor element that carries electrical current in two directions.
  • Diode – a unidirectional semiconductor that opens from the forward flow of electric current and closes from the reverse. – Capacitive element, the main task of which is accumulation of the desired amount of charge on the plates. It is better to use a non-polar model to make homemade dimmers. – are an active resistance, for dimmers are used in voltage dividers and current draw circuits. Both DC and AC resistors are useful in circuits.
  • LEDs – are useful for providing light indication in the dimmer.

Depending on the specific circuit and device of the dimmer, will depend on the set of necessary parts, all of the above do not need to purchase. Note that some of them can be soldered out from old TV radios and other household appliances that you no longer use. Below we look at examples of specific circuits.


This dimmer will run from 220V directly, the circuit is relatively simple and even a novice radio amateur can assemble it. The principle of voltage regulation in this dimmer is to cut off a certain half-period of the sine wave, so that reducing the electrical parameter leads to real energy savings.

Look at the wiring diagram, the triac is an electronic switch, which is controlled by signals from the dinistor included in the time-charging R – C chain.

Diagram of a dimmer on a triac

Diagram of a triac dimmer

Operation of the circuit is as follows: after connecting 220V phase to the dimmer, voltage will be applied to the time-charging circuit C1 – R1 – R2, since the dynistor VS1 is closed, the current flows only through the capacitor and resistors.

Depending on the ohmic resistor set by the rotary resistor the amount of current will also depend on the amount of current. The rate of charge of the capacitor C1 depends on the value of the current, and when it reaches the desired value of the potential on which the diistor will open.

Through the circuit of the opened diistor an open signal is given to the triac VS2, the switch is actuated, allowing a certain part of a half-period to the load. There is no holding current in the triac, so as the capacitor discharges the whole circuit goes back to its original state until the next half-period, which will open the key and apply potential to the load.

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Variation of sine wave

Changing the sine waveform

As you can see, this dimmer circuit performs brightness adjustment by “cutting” the sinusoidal shape to a certain pulse, reducing both the magnitude of the voltage and its effective value. In view of the unstable fluctuation of the curve, this model of dimmer can definitely be connected to incandescent lamps, because they are not susceptible to the shape of the voltage. As for LED and fluorescent models, they need to be tested on a ready-made dimmer.

To make such a dimmer for practical use, it is better to take a printed circuit board. Because in a stationary installation, you will need a rigid attachment to the design when regulating the voltage. You can either order it or make it yourself.

The assembly process consists of the following steps:

If you have marked the mounting pads, stick to this marking.

On thyristors

This model of dimmer on thyristors on the principle of operation is identical to the previous version, but instead of a triac, thyristors act as a key. Because of the peculiarities of thyristor operation it is more appropriate to install such an electronic device for each half-wave of the voltage sine wave.

An example of such a dimmer circuit is shown in the figure below:

 Diagram of dimmer on transistor

Diagram of the regulator on thyristors

Let’s start analyzing circuit’s work with the positive half period of the voltage curve – the capacitor C1 is being charged by the circuit with current limiting resistors R3 – R4 – R5. When the charge reaches the threshold value for diistor V3, it opens and supplies a control pulse to thyristor V1. In key mode, V1 begins to pass voltage to the load, producing a certain portion of the voltage curve.

During the negative half-cycle of the sinusoid V1 will lock, no current will flow through it, and the capacitor C2 will receive a charge through the current-carrying circuit R1 – R2 – R5, which will eventually open the diistor V4. Through it will flow current to the control electrode of the thyristor V2, after the opening of the transistor on the load will go the same part of a half-period of a sine wave, but with the opposite sign.

Such light output controller can be used not only to change the brightness of lamps, but also to control the temperature of a soldering iron and other devices.

Using capacitors

Such a dimmer works only as a switch that changes the path of the current flow that feeds the load. But also the circuit of the push-button dimmer is quite simple and will not require any specific elements.

Diagram of dimmer on capacitor

Diagram of a dimmer on a capacitor

The principle of its work is to set the switch SA1 to one of three possible positions:

  • off – the circuit is completely open, the lamp is not lit, or the pass-through switch produces a logical zero in the circuit;
  • shorted to the lamp – there are no elements in the dimmer connection circuit except the electric lamp (the light fixture lights up at full power);
  • connected through R – C circuit – outputs only a certain percentage of lighting brightness.

Depending on the parameters of the resistor and capacitive element will depend on the voltage and brightness of the light. This dimmer is used to regulate the light by dissipating some of the power in the R – C circuit, so you will not get any savings from the reduction.

On the chip.

In a dimmer built on a chip, the voltage is changed for 12V consumers – LED strips, fluorescent lamps and other equipment. One version of the circuit is shown in the figure below.

Diagram of dimmer on a microcircuit

Diagram of a dimmer on a microcircuit

As you can see, it can be controlled by a sensor connected to pin 2 and also by the variable resistor VR1.

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The chip outputs a control signal from pin 3 through resistor R2 to the base of transistor VT1. By changing the voltage with variable resistor VR1, the output 3 of the chip changes the potential level, which increases or decreases the bandwidth of the transistor. At the same time the brightness of the LEDs also changes, if the LEDs are controlled.

Diagram of a dimmer for LED lamps on 220V

Dimmers in lighting technology create a pleasant comfortable light. They help save energy and can extend the life of the bulbs used. Examples of dimmers in the home include vacuum cleaners that reduce suction power with a rotary knob, as well as laptop chargers that reduce screen illumination. In order to operate these devices properly, you need to understand how a dimmer works.

How a dimmer works

Dimmer (dim) is an electronic device that has the ability to switch electrical currents . In Russian it is called a dimmer, and in French it is called a variator. The mains voltage is 220 V AC. This means that it changes its polarity every hundredth of a second and always goes through zero (sine curve). With the dimmer knob, the user sets when the lamp should light up during the sine wave half-wave. This control principle is called phase control in electrical engineering.

Some lamps work with dimmers, on the principle of phase section . Since both types of control cause very fast switching, the lamp does not keep up with these changes due to inertia, so the light does not flicker. Traditional dimmers have a rotary knob or touch control that, in addition to turning the light on and off, allows you to adjust the brightness . Choosing a dimmer, the main thing is to know what bulbs can be used with it.

Nowadays, the standard of lighting in the room has changed. In many countries, incandescent bulbs are banned. There is a mass replacement for LED or energy-saving lamps. They are mostly used with dim controls, which are designed to regulate brightness.

With a light touch…

Another type of dimmer is the touch dimmer. With a light touch of your hand, it’s easy to control the lights, change the speed of the motor. The load at the output can be anything from LED strips, to powerful spotlights of several kilowatts. But the circuit is also a bit more complicated.

The main element is the HT7700C/D chip. It is a CMOS device designed for continuous brightness control. The triac is chosen for the required power, taking into account that the current on pin 5 of the chip is 14 mA. Supply voltage: 9-12 V. The sensor is connected through a diode to pin 2.

The sensor can be any metal plate or a piece of bare copper wire. It all needs to be nicely decorated.

The device works like this: first touch – on. The second touch dims the brightness step by step, the third touch locks the brightness. The fourth touch – off.

As you can see, it is possible to assemble a dimmer with your own hands. It will allow you to save on the purchase and try your hand at electronics.

The right choice of dimmer

There are different models of dimmers, as well as types of load, which affect the correct choice of device . Dimmer is chosen according to the load of lighting fixtures. This information can be found on the manufacturer’s packaging and on the lamp. There are many different adjustable lighting devices on the market:

  1. High-voltage high-power halogen, 220 volt (G9 or GU10 socket).
  2. Low-voltage 12V DC lamps with electronic transformer, socket G4, GU5, 3, GY6, 35.
  3. 12 V common socket G4, GU5, 3, GY6, 35.
  4. LED lamps, various types of sockets.
  5. Energy saving lamps, all types of socket.

Industrial markings for dimmers: the letters R, L or C. They can be seen on the lamp housings. For the correct choice of dim they must match. You must pay special attention to this requirement before you buy the lamps, otherwise they will not work.

Types of lamps compatible with dimmers:

  1. Dimmable energy-saving lamps (ESL).
  2. 230V LED lamps and high voltage LED lamps marked as dimmable.
  3. 12V AC and 12V DC. LED lamps should also be marked as dimmable.
  4. LED strips and single LEDs (DC) with optional LED ballast integrated into the PWM dimmer.
  5. Dimmable LED drivers are also available for different types of control.
  6. Fluorescent lamps with special 0-10V ECG ballasts.
Charger Schematics

Helpful hints

Study the product data sheet carefully. Some dimmers are noticeably warm, so the manufacturers prescribe their use with restrictions. For example, dimmer Dimmat German company Kopp not recommended to include a load of more than 300 W, if the temperature in the room exceeds +25 C: but the maximum power, declared in its characteristics, is 400 W.

Such requirements should be taken with particular attention if the wall, on which the device is supposed to be fixed, is made of materials with low thermal conductivity, such as wood or plasterboard. You should know that the efficiency of a light bulb, “screwed” with a dimmer, is greatly reduced

Therefore, if you have to use the lamp most of the time in reduced brightness mode, it is advisable to replace it with a less powerful and use the latter without a dimmer

You should know that the efficiency of a light bulb, “screwed” with a dimmer, is greatly reduced. Therefore, if you have to operate the lamp most of the time in a reduced brightness mode, it is advisable to replace it with a less powerful and use the latter without a dimmer.

All modern dimmers have a fuse, so it makes sense to buy at least one spare in advance.

Please note! When a low-inertia light source, such as an LED strip or discharge lamp, is reduced with a dimmer, a stroboscopic effect occurs. Moving or rotating machinery and tools can appear to be stationary in this light, which can be very dangerous.

For this reason dimmers should be used with caution in workshops and production facilities

Types of electronic light dimmers

The choice has never been more difficult than it is now: all because of the many different designs and brands. The introduction of LED lighting to the mass market has changed its style. To know which dim you need to buy, you first need to determine the scheme of electric lighting installed in the house, then choose the type of control device: touch, when it is controlled by hand, mechanical, rotary or other.

  1. Universal is the easiest option to install. It can reduce almost all types of loads and thus makes choosing the right lamp much easier. Advantage. Even if the user decides to change the lamp or load type later, no new one will be needed.
  2. LEDOTRON is the standard. They are only used with branded lamps from the manufacturer LEDOTRON.
  3. For electronic transformers, controls with reverse phase for dimming, such as lamps with low-voltage halogen lamps. These transformers are often cleverly integrated into the lamp housing.
  4. For conventional transformers (phase control dimmer). Inductive loads can be dimmed with phase control.
  5. Rotary, classic with a knob.
  6. Easily switched on by pushing with the finger.
  7. Foot-operated for control, such as with floor lamps.
  8. Direct, brightness level selection via LEDs.
  9. Serial, control of several lamps or groups of lights.

Speed controller for 12V motor or dimmer for lamps

This circuit can be used as a speed controller for a 12V motor with current up to 5A (constant) or as a dimmer for a halogen or standard 12V incandescent bulb up to 50W. Depending on the load (motor or lamp), the power changes by pulse width modulation (PWM) with a pulse frequency of about 220Hz.

Silicon Chip has been producing various speed controller chips for 12-24V and 20-40A current for many years.

However, for most applications it is enough to build a simpler and cheaper design. That’s why we present this basic design, which uses a 7555 timer and a field effect transistor.

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Dimmer with his hands

Being a simple design, it does not control motor EMF to provide improved speed control and also has no sophisticated overload protection other than a fuse. Nevertheless, it is very efficient with a low cost parts kit.

Dimmer with his hands

There are many applications for this circuit where 12V motors, fans or lamps are used. You can use it in cars, boats, and recreational vehicles, in model boats and railroads, and so on. Want to control a 12V fan in your car or computer? This circuit will do it for you.

Dimmer with his hands

The circuit on the 7555 timer generates pulses of variable width at about 210 Hz which go through Q1 and Q2 to the field effect transistor Q3 to control the motor speed or the lamp brightness.

Although the circuit can dim 12V halogen lamps, it should be noted that using halogen lamps in this mode is very wasteful. In situations where you need dimmable lamps, it is much better to use 12V LED lamps, which are now available with various standard bases, including MR16 for halogens. Plus, they heat up a lot less and will last longer.

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Pros and cons of connecting

Some people like dim, while others not so much. However, they are very useful in many situations. Dimmer switches are fairly easy to install and affordable for residential use. Before deciding to install dimmers in your home, it is advisable to familiarize yourself with some of the pros and cons of this lighting option. Advantages of installing switches:

  1. Energy savings. You can save up to 25% in costs by reducing the light by 25%.
  2. Complete control over the lighting process in the home.
  3. Autonomous operation with remote control, which allows you to adjust the lighting in any room from an accessible location in the Smart Home system.
  1. Difficult to install for inexperienced users. Although dimmer switches are relatively simple, they can be confusing to those unfamiliar with electronics. The easiest solution to this problem is to hire an electrician to wire the switch. Although this will increase the cost of the project, it will ensure that it is done correctly.
  2. Incompatibility with some lighting fixtures. Research is recommended to see if dim switches will work with existing lighting on site.

Top 3 soldering irons for boards.

To assemble a quality circuit that will last for many years, it is advisable to purchase a good soldering iron. There are well-known manufacturers on the market who have managed to prove the quality of their products:

  1. The German company Ersa. Fingers are very good, but the manufacturer has a significant disadvantage – the products are sold at a high price, and therefore purchased mainly for professional use.
  2. Quick – a Chinese company that is not inferior in quality, but produces models at affordable prices.
  3. The budget version of Luckey. This model is ideal for beginners. But you can not leave the device unattended – there were cases of fire.

Look at the picture of a complete soldering iron for microcircuits:

To choose a good soldering iron for boards, you need to look carefully at its main characteristics. The power of 10 W is suitable for the assembly of simple microcircuits – a sufficient level of heating and do not have to worry about overheating the circuit. For home use you can buy one with 20 to 40 Watt. You will not need more power, because such soldering irons are already used to work with radiators and metals.

Pay special attention to the study of the handle. It should not heat up when working – otherwise your hands will suffer

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It is desirable to choose this detail from wood. Plastic will heat up very soon, and ebonite will weigh the whole device and it will be inconvenient to work with small parts. Therefore wood is the most suitable option both in terms of resistance to heat and convenience.

Pay attention to the sting, too, when buying. Copper is the most suitable option, because it will be easier to handle, to clean the sticking fouling

Often models are available with a set of stingers that vary in shape. This is very convenient for soldering microchips – you can adjust the length. Straight sting is suitable for training beginners, but experienced users can also use with different bends at different angles.

Automatic light control

In many cases, an automatic dimmer can be built into a wall box with a light switch. It is designed for use with 220V incandescent bulbs only. When it is installed and the light is on, the light stays on completely for about 400 ms, which is imperceptible to the human eye for about 20 s, and then gradually goes out. This gives the advantage that when the light is off, it doesn’t immediately go dark. When S1 is on, capacitor C2 is charged via R1, C1 and bridge rectifier D1 – D4.

It is also important to know 3 other things about soldering the boards

To solder wires and boards, you need to be aware of a few important nuances of the job:

  1. Before starting the operation, it is imperative to find a good soldering iron. An ordinary soldering iron will not do because of its power. The voltage range of the device for soldering boards and wires is 15-30 watts. It is forbidden to use more power, otherwise the board will burn out.
  2. Before you start, the board qualitatively clean the board for a good connection of all elements. For processing, we mix soap with water, dip the cloth in the solution and carefully wipe the board. The metal after treatment should be cleaned very well from the soap. Sometimes you can see thick deposits on the boards – they are removed with a special compound, sold in a store of electrical goods. The area is scrubbed until it has a metallic luster.
  3. The contacts on the board must be positioned correctly. First connect the small resistors, and then move on to the large parts.

Diode circuit in the charger

The use of a dimmer circuit in a laptop charger began to be used at the same time as their release. Manufacturers have always been concerned about saving battery power in laptops, so dim monitor shows the opposite behavior. When it is plugged in and the battery is charging, the screen gets darker. When the battery is on, the screen glows brighter. The battery icon arranged on the screen (plug when plugged in).

The charging details in the power meter show the correct operation of the regulator. This process can be adjusted by the user in the power section of the laptop, at the bottom right of the desktop. It is set as desired by the owner in three modes: balanced, power saving, high performance. When using the latter scheme, the laptop power draws a lot of current and the battery drains quickly.

Making a brightness controller

Many people cannot sleep in a brightly lit room as well as in complete darkness. A dim light source, such as a night light, is the best device for a comfortable sleep, which is what a dimmer is for. In addition, economical night light uses very little electricity and will save the household budget. Make a night light with your own hands is not difficult. The principle of night light is simple – the light will automatically dim and turn off after a certain period of time, which is set by the user.

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