To adjust the brightness of incandescent lamps, special regulators are used. These devices are also called dimmers. They exist of various modifications, and if necessary, in the store you can always pick up the necessary model. Basically, they replace a switch in an incandescent lamp. The simplest modification includes one rotary controller with a handle. When adjusting the brightness, the indicator of electricity consumption also changes.
If you recall the old days, the knobs to adjust the brightness were not used. Instead, special rheostats were installed. With their help it was also possible to regulate fluorescent lamps. In general, they coped well with their duties, but they had one drawback. It is associated with electricity consumption. As mentioned earlier, modern regulators consume less electricity if they are not used at full capacity. In the case of rheostats, this rule does not apply. At minimum power, electricity is consumed in the same way as at maximum. Surplus in this case is converted to heat.
Regulator circuit
A simple dimmer circuit involves the use of a linear type potentiometer, as well as a pair of transistors with low power. Capacitors are used to suppress high frequency in the system. Cores in devices of this type need only ferrite type. A dinistor with a thyristor is installed directly in front of the terminals.
How to install the rotary control in the lamp?
In order for a table lamp with a dimmer to work normally, you should check the voltage on the semiconductor. This can be done using a conventional tester. Next, inspect the incandescent lamp board. If it is installed of a single type, then everything is quite simple to do. It is important to connect output semiconductors to output openings that have a negative polarity. In this case, the maximum resistance should be 3 Ohms. To check the device, it is necessary to turn the controller and monitor the brightness of the incandescent lamp.
Installing a push button control in the lamp
In order for the incandescent lamp dimmer to work properly, it is important to carefully read the device’s management board. Next, you need to connect all the contacts. If the circuit is multi-channel, then the voltage on it is checked by a tester. Directly connecting the contacts is carried out by soldering. It is important that during operation do not touch the resistors. Additionally, care must be taken to isolate the wiring. Before turning on the regulator, check the reliability of all connections. After applying power, you must try to change the brightness by pressing the button.
High voltage dimmers
High-voltage dimmer, as a rule, can be found in theaters. There, incandescent lamps are used quite powerful, and devices must be able to withstand heavy loads. Triacs are used for this purpose high-voltage (marked KU202). Transistors are used bipolar, but their usual modifications are also installed.
Diode bridges are soldered near the thyristors and are necessary for fast signal transmission. Zener diodes can most often be found with the marking D814. They are quite expensive in the store, and this should be taken into account. Variable resistors in the system limit voltage capable of withstanding at 60 ohms. At this time, ordinary analogs are fused with only 5 ohms.
Precision Resistor Models
A dimmer with resistors of this type is designed for medium power incandescent lamps. Zener diodes in this case are used at 12 V. Variable resistors in regulators are quite rare. Low-frequency modifications can be used. In this case, the conductivity coefficient can be increased by increasing the number of capacitors. Behind the triac they are obliged to settle down in pairs. In this case, the heat loss will be minimal. Negative resistance in the network is sometimes a serious problem. Ultimately, overload leads to a breakdown of the zener diode. Electrolytic capacitors with low-frequency noise cope quite successfully. The main thing in this case is not to give a sharply high voltage to the lamp.
Regulator circuit with high-resistance resistors
A dimmer of this type can be used to control various types of lamps. Its circuit includes high-resistance AC resistors , as well as a conventional zener diode. The thyristor in this case is installed next to the capacitor. To reduce the limit frequency, experts often use fuses. They are able to withstand a load of 4 A. At the same time, the maximum output frequency will be a maximum of 50 Hz. General purpose triacs can withstand input voltage of 15 V.
Field Effect Transistor Switches
Switches with a dimmer on the field effect transistor are well protected. Short circuits in the system are quite rare, and this is undoubtedly an advantage. In addition, it should be noted that zener diodes for regulators can only be used with the marking KU202. In this case, they are able to work with low-frequency resistors and cope well with interference. Triacs in the circuits are located behind the resistors. The maximum resistance in the system must be maintained at 4 ohms. The voltage at the input of the resistors holds about 18 V. The limit frequency, in turn, should not exceed 14 Hz.
Regulator with trimmer capacitors
A dimmer with trimmer capacitors can be successfully used to adjust the power of fluorescent lamps. The switches in this case should be located behind the diode bridge. Zener diodes in the circuit are needed to suppress interference. Variable resistors, as a rule, limit resistance withstand at 6 ohms.
At the same time, thyristors are used exclusively to maintain voltage at the proper level. Triacs through themselves are capable of passing current at a level of about 4 A. Fusible fuses in regulators are quite rare. The problem with electrical conductivity in such devices is solved by using a variable output resistor.
Simple thyristor model
A dimmer with simple thyristors is most suitable for push-button models. The protection system, as a rule, is absent in it. All contacts in the controller are made of copper. The maximum resistance at the input of a conventional thyristor can withstand 10 V. For rotary controllers, they do not fit well. Precision resistors with such regulators are not able to work. This is due to the high level of negative resistance in the circuit.
High frequency resistors are also rarely installed. In this case, the interference level will be significant and will lead to an overload of the zener diode. If we talk about ordinary table lamps, it is best to use a conventional thyristor coupled with wire resistors. Their current conductivity is at a fairly high level. They rarely overheat, the power dissipation fluctuates on average around 2 watts.
Using variable capacitors in a circuit
Thanks to the use of variable capacitors, it was possible to achieve a smooth change in the brightness of incandescent lamps. In this case, electrolytic models work completely differently. Transistors for such capacitors are most suitable for 12 watts. Input voltage should be maintained at 19 V. The use of fuses should also be considered. Thyristors are usually used with the marking KU202. For rotary modifications, they fit well. To increase the conductivity coefficient, potentiometers are used with circuit breakers.
Single-junction controller device
The one-junction dimmer is famous for its simplicity. Resistors in it are usually used at 4 watts. At the same time, he is able to keep the voltage maximum at a level of 14 V. When using it, it is important to consider that during operation the bulb may flicker. Fuses are rarely used in devices.
At the input, the rated current maximum can leave 4 A. Thyristors of the KU202 type are capable of working in such a system only with a diode bridge. The triac in the device must be connected behind the resistor. To connect the dimmer to the lamp, you need to strip all the contacts. The housing for the device is important to use dielectric. In this case, work safety will be guaranteed.