What Will I Learn?
In this tour you will learn:
Basic management of the Oregano software for analysis of electronic circuits.
Analysis of electronic circuit to modify a sine wave.
Measure voltage in different nodes of the circuit and represent their behavior in stages through graphs.
Requirements
This program works under the LINUX operating system.
Basic knowledge of the operation of Zener diodes and Diodes.
Basic knowledge of the concept of nodes and meshes.
Difficulty
- Intermediate
Tutorial Contents
This tutorial is a contribution from the 
Oregano is a simulator of electrical circuits that will allow us to create schemes with resistors, coils, capacitors and electronic devices such as diodes, Zener diodes, potentiometers, transistors, LEDs, operational amplifiers, among others.
In the following image you can see the main window of the Oregano, and its component menu is indicated, in the upper part we will find the necessary tools to create a new design and compile the circuit, in the right side we will find the elements that are used for the design of the circuit to use in this tutorial.
Oregano includes a schematic window to design the electronic circuit, in addition it has a variety of libraries of electronic components, to have a wide possibility of design. It also offers different types of analysis for circuits: time analysis, AC frequency response, response to continuous DC values, among others.
With the example shown in the figure below, a design of electronic circuits with rectifier diodes and Zener diodes is observed, we will develop a circuit to modify the waveform of a sinusoidal signal, limiting its voltage value by activating the semiconductor diodes.
To begin, we proceed to select the different components that make up the circuit we want to design, so we add to the diagram the resistors as linear elements, diode rectifiers, Zener diodes as non-linear elements and the generator of sine waves as an AC source. Follow the example in the figure below:
When you double click on each element, enter the properties menu and proceed to configure the operation values of each component. In the following image I observed the configuration of the AC power supply and a rectifier diode.
Once all the elements have been configured, the connection lines of the circuit are created, these lines connect the different nodes of the circuit, the connection function must be selected from the toolbar, where the figure of the pencil appears with a blue line.
Accompanied by each node, the test points must also be located to verify the voltages in each node and allow the analysis of the waveform in the different phases of the circuit. To locate the voltage measurement element is located in the toolbar called test point. Observe the figure below:
Once all these steps have been carried out, the simulation parameters of the circuit must be modified, this is done by clicking on the "simulation parameters" region located on the toolbar, as shown in figure. It is mandatory to carry out this step in order to obtain a legible graphic at the time of the simulation since the time or period of the signal depends on it. In the figure shown below you can see the configuration for the sweep of the graph with a step that I also set as the best step for the result that you want to achieve in this design.
In the simulation we observe the response in time, AC, DC and Fourier analysis. For the case study that we are developing, we only need the response of the sinusoidal signal as a function of time, to see how the program modifies the waveform. Each test point that is connected in the different nodes of the circuit is identified in a graph of the waveform as a function of time. The following figure shows all the graphs that correspond to all the test points located in the nodes of the circuit.
Another important aspect to highlight is that to observe the behavior in the nodes we must activate them by clicking on each of them, whose location is in the graph window.
Circuit analysis
The first branch of the circuit activates two polarized Zener diodes in reverse, generating the cutoff of the maximum values of the sinusoidal signal, as seen in the graphical signal. The following figure shows the curve for each node highlighted in the black circle.
The next branch activates the diodes in series, polarized in direct and inverse for each cycle of the signal, causing a voltage drop equivalent to the junction voltages of each diode and a voltage divider as seen in the green output graph of the sinusoidal signal.
Finally, the behavior of both branches is observed in comparison with the input signal provided by the AC source, which is distinguished by the white color of the curve.
In this way, we finished this introductory tutorial to learn how to use the oregano circuit simulator for the analysis of an electronic circuit with rectifiers of diodes and Zener diodes to modify a sinusoidal signal, it is worth noting that the example we use helps to attenuate the signal, however, other branches with Zenner diodes or diodes can be added to find a square or triangle signal for some application that we wish to give to this type of wave. This explanation will be given in a next tutorial, in order to continue this incredible open source simulator, which is of great help to all electronic designers. This first explanation will allow us to have the basic knowledge of the management of the Oregano and also a basic analysis of circuit design. I hope you have found them useful in a future turorial.
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