How to Do Transient Analysis in PSPICE

July 14, 2025

Cadence PCB Solutions

Key Takeaways

PSpice transient analysis lets you simulate circuits' time-dependent behavior, which is ideal for observing startup, switching, or oscillation dynamics.
With OrCAD X and PSpice, setup is simple: define a simulation profile, configure time-domain parameters, and visualize results with probes.
The Checkpoint Restart feature speeds testing by letting you resume simulations from saved points—perfect for tuning components post-startup.

Buck converter circuit simulated with transient analysis in OrCAD X showing voltage and current over time.

Transient Analysis of a buck converter circuit in OrCAD X

Understanding how a circuit behaves over time, especially when subjected to changing inputs or switching events, is crucial for verifying its functionality and stability. These conditions are where transient analysis becomes an indispensable simulation tool. PSpice, integrated within the OrCAD X environment, allows engineers to perform detailed time-domain simulations, which calculate circuit responses—such as -voltages and currents—as they vary continuously over time due to dynamic or non-steady-state conditions. This guide will walk you through how to do transient analysis in PSpice, from setting up your circuit to interpreting the results.

Why Perform Transient Analysis?

Aspect	Description	Example Use Case
Time-Domain Response	Evaluates how circuits respond to time-varying inputs like steps, pulses, or sine waves.	Analyzing the output waveform of a low-pass RC filter with a pulse input.
Startup Behavior	Shows how voltages and currents evolve when the circuit is first powered on.	Observing how a power supply ramps up voltage when first turned on.
Switching Characteristics	Analyzes the behavior of switches and transistors (e.g., in DC-DC converters or digital circuits).	Checking voltage spikes and switch timing in a buck converter.
Oscillations & Stability	Helps detect undesired oscillations and assess damping in resonant circuits (like RLC networks).	Investigating ringing in an LC tank circuit or amplifier feedback loop.
Timing Parameters	Measures rise/fall times, delays, and pulse widths critical in digital and analog design.	Verifying timing constraints in a logic gate or clock pulse chain.

Setting Up for Transient Analysis in OrCAD X

Set up your OrCAD X environment and schematic before learning to do transient analysis in PSpice.

PSpice-Enabled Project:

When creating a new project (File > New > Project), make sure the "Enable PSpice Simulation" checkbox is selected. This selection activates the PSpice menus and toolbars necessary for simulation.
If opening an existing project, confirm if PSpice is enabled.

Time-Domain Source:

Transient analysis requires a time-varying input source to observe a dynamic response. Common PSpice sources for this include:

Pulse: For generating square waves, pulses, or step functions. You'll define parameters like initial voltage (V1), pulsed voltage (V2), time delay (TD), rise time (TR), fall time (TF), pulse width (PW), and time period (PER).
Sine: For sinusoidal inputs, defining offset, amplitude, frequency, and phase.
PWL Sources: For creating arbitrary piecewise linear waveforms defined by time-voltage/current pairs.

Place these sources using Place > PSpice Component > Source or via the Modeling Applications (Place > PSpice Part > Modeling Application), which provides a guided interface for setting source parameters.
You might replace a DC source with a VPULSE source for an RC circuit to observe the capacitor charging and discharging.

PSpice Models: Ensure all components in your circuit (resistors, capacitors, inductors, transistors, ICs, etc.) have valid PSpice simulation models. It’s not possible to simulate generic schematic symbols without models.

The Modelling Application allows you to create many voltage sources with simple inputs

Getting Started with Transient Analysis in PSpice

Step	Action	Details / Description	Notes / Tips
1	Create a New Simulation Profile	In OrCAD X Capture go to PSpice > New Simulation Profile. Name it (e.g., Transient_Pulse_Response), then click Create	Use descriptive names for clarity and project tracking
2	Configure Transient Analysis Settings	The Simulation Settings dialog opens automatically	Located under Analysis type: Time Domain (Transient)
	Set Run to Time	Total duration for simulation (e.g., 5ms, 100µs)	Ensure it's long enough to capture full circuit behavior
	Start Saving Data After	Set to 0 to record from the beginning or specify a delay (e.g., 1ms) to skip transient startup	Useful for focusing on steady-state behavior
	Maximum Step Size (Optional)	Leave blank for automatic adjustment or enter a value for higher resolution (e.g., 10ns)	Helps with fast signal transitions or noise smoothing
	Save Settings	Click Apply, then OK	The simulation profile is now ready
3	Place Voltage/Current Probes (Markers)	Use toolbar icons or PSpice > Markers	Required to visualize data post-simulation
	Voltage Probes	Place on the nets or component pins	Measures voltage relative to ground
	Current Probes	Place directly on component pins	Measures current into/out of a device

Transient Analysis Simulation Settings

How to Do Transient Analysis in PSpice

Step	Action	Details / Description	Notes / Tips
4	Run the Simulation	Click the green Run PSpice icon or go to PSpice > Run	Starts the transient simulation using your profile
5	Analyze Results in Waveform Viewer	Opens automatically when the simulation completes	Visualizes voltage and current waveforms
	Reading Waveforms	X-axis: time, Y-axis: voltage or current; traces are color-coded	Matching trace names with probes simplifies analysis
	Add Plots & Traces	Creates new Y-axis plots: Plot > Add Plot to Window, then add new markers Select node voltages, device currents, or expressions: Trace > Add Trace	Use separate plots for voltage and current for clarity
	Add Cursors for Measurement	Enables cursors: Trace > Cursor > Display	Track voltage/current levels at specific times, measure time differences, peak values, and rise/fall times
	Save Plot Configurations	Probe Window Settings > Last Plot	Reuse display settings across runs or for documentation

Reuse Plot Setup with "Last Plot" in the Probe Window

Advanced Transient Analysis Feature: Checkpoint Restart

PSpice Checkpoint Restart feature allows you to save the simulation state at defined intervals during a transient run and restart from any of these points later, even after modifying component values. This feature significantly reduces simulation time, especially for circuits with long startup transients or when validating steady-state behavior after small design changes. It's ideal for improving efficiency during iterative design and analysis workflows.

How to Use Checkpoint Restart

Enable Save Checkpoint: In the Simulation Settings (Transient analysis), check the "Save Checkpoint" option. Specify the file path for saving checkpoints and the "Simulation interval" at which states should be stored (e.g., every 1ms).
Run Initial Simulation: PSpice will save checkpoints at the specified intervals.
Restart from Checkpoint: To restart, go back to Simulation Settings. Deselect "Save Checkpoint" and select "Restart simulation." Choose the desired simulation time (e.g., 3ms) from the dropdown menu of saved checkpoints.
Re-run: The simulation will start much faster, beginning from the selected checkpoint time.

Restart your simulation checkpoint at any time.

Any circuit designer must know how to do transient analysis in PSpice. Whether you're analyzing the response of a simple RC filter, the switching characteristics of a buck converter, or the stability of an amplifier, transient analysis in PSpice provides the flexibility to virtually test and validate various designs before hardware development, saving time, money, and materials in the long run.

Ready to explore the dynamic world of your circuits? Try OrCAD X for free, which includes PSpice, or explore the complete OrCAD X platform to unlock even more advanced simulation and analysis capabilities.

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