## Making Shapes with PSLab Oscilloscope

Looking back to history, the first ever video game was ‘Pong’ which was played on an analog oscilloscope with a very small screen. Oscilloscopes are not made to play video games, but by just tinkering around its basic functionality which is display waveforms, we can do plenty of cool things. PSLab device also has an oscilloscope; in fact it’s a four channel oscilloscope.

This blog post will show you how the oscilloscope in PSLab is not just a cheap oscilloscope but it has lots of functionalities an industry grade oscilloscope has (except for the bandwidth limitation to a maximum of 2 MHz)

To produce shapes like above figures, we are using another instrument available in PSLab. That is ‘Waveform Generator’. PSLab Waveform Generator can generate three different waveforms namely Sine waves, Triangular waves and Square waves ranging from 5 Hz to 5 kHz.

To get started, first connect two jumper wires between SI1-CH1 and SI2-CH2 pins. We needn’t worry about ground pins as they are already internally connected. Now it’s time to open up the PSLab oscilloscope. Here we are going to utilize two channels for this activity and they will be CH1 and CH2. Check the tick boxes in front of ‘Chan 1’ and ‘Chan 2’ and set ‘Range’ to “+/-4V” to have the maximum visibility filling the whole screen with the waveform.

The shapes are drawn using a special mode called ‘X-Y Mode’ in PSLab oscilloscope. In this mode, two channels will be plotted against their amplitudes at every point in time.

As it is already mentioned that PSLab can generate many waveform types and also they can have different phase angles relative to each other. They can have different independent frequencies. With all these combinations, we can tweak the settings in Waveform Generator to produce different cool shapes in PSLab oscilloscope.

These shapes can vary from basic geometric shapes such as circle, square, rectangle to complicated shapes such as rhombus, ellipse and polynomial curves.

**Circle**

A circular shape can be made by generating two sine waves having the same frequency but with a phase difference of 90 degrees or 270 degrees between the two wave forms.

**Square**

Square shape can be made by generating two triangular waveforms again having the same frequency but with a phase difference of either 90 degrees or 270 degrees between the two.

**Rectangle**

Similar to creating a Square, by having the same frequency for both triangular waveforms but a different phase angle greater than or less than 90 degree will do the trick.

**Rhombus**

Keeping the waveform settings same for the rectangle, by changing the amplitude of the SI1 waveform using the knob we can generate a rhombic shape on the XY graph plot.

**Ellipse**

Generating ellipse is also similar to creating a rhombus. But here we are using sine waves instead of triangular waves. By changing the amplitude of SI1 using the knob we can change the curvature.

**Helix**

Helix or spiral shape can be generated using two sine waves having same phase but two different frequencies. Frequencies better be integer multiples of the smaller frequency to have a steady shape.

**Parabola**

Parabolic shapes can be generated by mixing up triangular waves with sine waves with different phase angles.

**More random shapes**

**References**:

https://www.aps.org/publications/apsnews/200810/physicshistory.cfm