Introduction to AC Dimmer of Tow Loads Using Single Controller: AC dimmer of two loads using single controller is a such type of device, that controls two linear loads simultaneously with the help of a single controller. it is a new technology for controlling ac power and could be easily used in electric oven, instant heater and motor etc. Conventional dimmers which are easily available in market have not property to control two loads simultaneously beside this, they do not change the power linearly. But this type of AC dimmer of two loads using single controller is specially designed for providing linear power of two loads.
This device has made up with the help of a power electronic components such as TRIAC, MOSFET, optocoupler, single phase transformer, bridge rectifier, voltage regulator, zero crossing detector, LCD display and single microcontroller PIC18F452, which belongs to pic family. This AC dimmer of two loads using single controller device is directly operated at single phase ac supply therefor no need of any other extra power supply. This device could be also used as a variable motor speed drive because when power change then motor speed changed automatically. This device is less costly, more efficient and more reliable as compared to other types of speeds dives or dimmers. The block diagram of this AC dimmer of two loads using single controller device with all their essential components is shown in figure 1
Block Diagram of AC Dimmer of Two Loads Using Single Controller
Figure 1 Block Diagram of AC Dimmer of Two Loads Using Single Controller with All their Essential Components
Working Principle of AC Dimmer of Two Loads Using Single Controller
This AC dimmer of two loads using single controller works on the principle of triggering pulse which is generated by the microcontroller. Microcontroller is actually the main intelligent controller of this device which is interfaced with zero crossing detector ,optocoupler 1,optocoupler 2 and LCD display. It is programmed in c language with the help of mikro/c software. Because, this device mostly consists of electronic components which are operated at 5 volts dc. Therefor when this AC dimmer of two loads using single controller device is turned on through 220 volts single phase ac supply then the transformer which is actually the step down ac transformer. It steps down 220 volts ac into 6 or 9 volts ac, then these voltages are converted into dc with the help of bridge rectifier. These dc voltages are not regulated therefor these are regulate through voltage regulator and for this purpose LM 7805 IC is used. These regulated voltages are used for turned on or off the microcontroller, LCD display and zero crossing detector. Here for the demonstration purposes we can use ac motor or ac lamp as an output load.
For turning on or off this load, zero crossing detector gives the trigging signal to microcontroller then microcontroller gives logic high signal to optocoupler which is interfaced with thyristor. Thyristor is a power electronic component which is turned on when positive signal pulse is applied at its gate terminal and turned off when negative signal is applied at its gate terminal. Through this negative and positive pulse the user can easily control the output voltages. Means we can easily change the output voltages from 10% to 100%. So at 10% output voltages the lamp intensity would be 10% of maximum intensity similarly the motor speed would be also at 10% of maximum speed. Thus by using this AC dimmer of two loads using single controller device we can control motor and lamp simultaneously without using any other controller. This device is friendly to use for everyone.