The figure 2 demonstrates the schematic diagram of the whole circuit.
Arduino sine wave dimmer.
This is a circuit that tells the arduino or another micro controller when the sinus wave goes through zero and therefore gives a defined point on that sinus wave.
In the last article we learned how to generate sine wave pulse width modulation or spwm though arduino we are going to use the same arduino board to make the proposed simple pure sine wave inverter circuit the design is actually extremely straightforward as shown in the following figure.
For a smooth signal we choose phase correct pwm at a frequency 31372 hz see previous post.
The square wave can be observed using a cro which is connected to the pin number 8 and the sine wave can be.
This circuit is only for incandescant bulbs.
Program developed by r girish.
The above chopped signal may not look like sine wave.
The figure 1 shows the mains sinusoidal wave with the frequency of 50hz sometimes 60hz.
To build a dimmer the zero crossing points the points where the wave changes its polarity are important.
A zero cross detector circuit is required for ac dimming purposes.
It is not for any inductive load as it is dc biased.
A real sine wave inverter s chopped wave form increase and decrease exponentially across x axis.
Demodulated waveform of variable frequency sine wave using arduino on cro.
Ac dimmer circuit made by using triac and optocoupler.
You just have to program the arduino board with the spwm code as explained in the.
When the coding is finished one can verify and upload the code to the arduino board as explained in the project how to get started with the arduino.
Second dim psm to control dim current.
Opening the triac after a number of microseconds delay starting from the zero crossing therefore gives a predictable level of dimming.
To generate a sine wave we will use two pins one for positive half cycle and one for negative half cycle.
The pwm signal of an arduino is faster than the 50hz frequency so you will basically see the pwm signal modulated on the 50hz rectified sine wave making the effective voltage lower.
In our post for this we use pins 5 and 6 that means timer 0.
First zero to control the passing of phase null of ac which is used to initiate the interrupt signal.
To grab these points we have to use a zero crossing detector.
But begin a simple design the chopping frequency stay constant and good enough to run most of electronic gadgets.
