In this Arduino electronics tutorial we will illustrate how dc bias voltage can be removed from signal using a capacitor. Arduino Due is used here to generate 4 different kind of signals- sine wave, triangle wave, sawtooth wave and square wave on its DAC0 pin. These signal are dc biased around 2V. The signals amplitude is around 1.2V with peak to peak of 2.4V. The signal is read by using Arduino Uno as signal acquisition hardware and signal waveform is plotted using p5.js on the browser.
Recommended Prerequisite
The codes used here for Arduino Due, Arduino Uno and the graph plotting program is in previous tutorial Real-Time Serial Graph with P5.js .
As mentioned earlier, the signal coming out of DAC0 of Arduino is dc biased which is shown in the picture below.
We can remove the DC bias using a 0.1uF capacitor to block the dc voltage and allow the ac signal to pass through it. Below is the circuit schematic which shows the 0.1uF capacitor used to remove the dc bias voltage from the signal coming out of Arduino Due DAC0 pin and into the analog pin A1 of Arduino Uno.
As said, the Arduino Uno is used to acquire the signal on its analog pin A1 and the serial data is plotted on real time graph made with P5.js. The real time graph below shows the DC biased removed from the signal.
Video demonstration
The following video demonstrates how to waveform shifts from its dc biased position to unbiased position by placing the capacitor.
