Amplifier design | Orcad Capture Tutorial

In the last altium designer tutorial we designed an CE amplifier that amplified a 10mV signal. In that tutorial we used voltage divider biasing technique in order to set the operating point for the amplifier. Here we will use the same schematic in orcad capture to verify its operation and the output input signal waveform in orcad capture. This will help us compare altium designer and orcad capture simulation result. Let's see if there is any differences.

Below is the recreated schematic in orcad capture.

Fig: CE amplifier design schematic

The voltage probe has been added at the input and output. The simulation settings are as shown below-

Fig: Simulation setup

After running the simulation we get the following signal waveform-

Fig: Simulation Result

The green waveform is the input signal and the red is the output signal waveform. As you can see the output signal is amplified and inverted in respect to the input waveform.

Let separate the signal waveform window. We can add net label to the wire where we want to collect the waveform data as in altium designer. The picture below shows Vin and Vout added to the schematic.

Fig: adding net label in orcad capture

In altium designer seperate waveform graph were shown. In orcad capture, we can do that by first going to Trace> Add Trace option in the toolbar and then select the Vout from the signal list. This is similar to the process in Altium Designer-

Fig: adding trace in orcad capture

The Vout waveform graph will be shown. Now we want to add another graph for Vin, for which you need to go to Plot> Add Plot to Window and a new plot window will appear as shown below-

Fig: adding plot window in orcad capture

Of course the new plot window is empty because we have not added any signal. To add Vin signal, again as before go to Trace> Add Trace and select the Vin signal and the signal should appear as shown below-

Fig: adding signal to new plot window

At first it looks like the Vin has greated amplitude than Vout but this is only because of the y-axis settings. We need to change the y-axis setting to -40mV and +40mV which can be done by right clicking on the upper Vin waveform graph and selecting the setting option. Then go to the Y-Axis tab and set the min and max as -40mV and +40mV. This is shown below-

Fig: changing y-axis setting

The final waveform graph for the input and output waveform is shown below-

The waveform graph as obtained from Altium designer simulation is also shown below for comparison-

Fig: Input,output waveform of the amplifer in altium designer

The simulation waveforms are same and there is not much change in the values of amplitude or phase.

Readers can go through the earlier post on designing amplifier where it was shown how the values of the resistors were calculated for the voltage divider biasing.