Operating Point #

Operating point analysis (.op) solves your circuit’s steady-state DC condition: the voltage at every node and the current through every branch, with no time-varying signals. It’s the fastest way to check that a circuit is biased correctly.

How to run it #

1. Build your circuit and place probes at the nodes you care about.
2. Open the oscilloscope and choose Operating Point.
3. Tap Run Simulation (or press Return).

Results show node voltages (referenced to ground) and branch currents.

When to use it #

• Verifying bias points in amplifiers.
• Checking a transistor is in the intended region (cutoff / linear / saturation).
• Confirming voltage-divider outputs and DC supply levels.
• A quick first step before running transient or AC analysis.

Example: transistor bias #

Probe the base, collector, and emitter of a common-emitter stage and run. For a silicon BJT you should see VBE ≈ 0.7 V and a collector voltage between the supply rail and ground.

If it won’t converge #

• Make sure every node has a DC path to ground (add a large resistor, e.g. 1 GΩ, to a floating node if needed).
• Re-check component values and connections.
• See Troubleshooting.