Oscilloscope

Electrically it is what a real scope probe is: 1 megohm from each channel to the ground clip. That is enough to load a high-impedance node the way a real probe does, and little enough to leave anything sane alone. It is in the part panel under Timers and analog.

Pins

Pin	What it does
CH1	Channel 1, 1 megohm to the ground clip. Drawn in yellow.
CH2	Channel 2, 1 megohm to the ground clip. Drawn in blue.
GND	The ground clip both channels are measured against.

The face

The screen shows both channels against time, over a 10 by 8 division graticule.

Two settings have buttons under the screen. The time base is on the left and the volts per division on the right, each with a - and a + that step 1, 2, 5 per decade, the way a real front panel is marked. The label above each pair shows the setting per division. Pressing them does not restart the circuit: the trace keeps running while you change range.

The strip along the bottom measures channel 1 off the screen: peak to peak, true RMS, frequency, and duty (how much of each cycle it spends high). TRIG in the top corner means the scope found a trigger edge.

The Scope tab

The Scope button in the bar above the serial monitor (under More on a phone) opens the same trace on a screen big enough to work on. It reads the same samples the face reads, so the two never disagree. When a circuit has more than one scope, a picker in the tab's header chooses which.

• Trace, XY and FFT views. XY puts CH1 across and CH2 up, for a Lissajous figure or a transfer curve. FFT is the spectrum of the 256 samples on the screen, through a Hann window, with the strongest peak marked.
• Nine measurements per channel: Vpp, Vmax, Vmin, Mean, Vrms, Freq, Period, Duty and Rise 10-90. A reading the screen cannot answer (one edge, no rising transition) shows --, not zero.
• Cursors: two time cursors and two voltage cursors you drag, with Δt, 1/Δt and ΔV read out. They work in the Trace and XY views.
• The trigger controls: source, slope, level (or automatic), mode and hold-off. They write the part's own properties, so they are saved with the circuit and undo like any other edit.
• A pin button beside each measurement and each cursor difference sends that reading to the lab notebook (the Notes tab).

There is no CSV export of the trace. To keep a number, pin it to the notebook, which exports its table as CSV.

Properties

Property	Default	What it does
window	0.02	The time base: seconds across the whole screen, from 0.0001 to 10.
volts	5	The vertical scale: the voltage at the top of the screen. The screen spans minus that to plus that, so 5 is 1.25 V per division.
source	ch1	Which channel the trigger looks for an edge on: ch1 or ch2.
slope	rising	Trigger on a rising or a falling edge.
mode	auto	auto draws the newest screen when no edge is found. normal keeps the last triggered screen. single holds the first edge until you press Re-arm in the Scope tab.
autolevel	on	Trigger at the middle of the source channel's own swing.
level	0	The trigger level in volts, used when autolevel is off. Drawn as a dashed line in the Scope tab.
holdoff	0	Seconds after one trigger before the next may fire. Use it to settle a burst that has two edges per cycle.
step	0	Forces the solver's time step on the circuit behind the probes, in seconds. Zero lets the solver choose. Set it to a small fraction of the time base if a fast edge looks like a staircase. It costs speed.

What the model gets right

The scope never creates an analog island on its own (clipping it to a digital net does not turn that net into a matrix problem), but it joins one that reaches it, so its 1 megohm input resistance counts whenever it matters. A channel with nothing clipped to it shows no trace, which is what a probe touching nothing tells you on a real bench too.

The screen is 256 samples, and the scope keeps four screens behind it so it can draw the newest whole screen that starts on the trigger edge. That is what makes a repeating waveform stand still instead of crawling. The frequency is measured from interpolated crossings, so it does not step in units of the sample rate.

What it does not model

• 256 samples a screen is the resolution. A feature narrower than about a hundredth of the time base is not in the picture, and the samples are point readings, so a narrow spike between two samples is simply missing.
• The probe is 1 megohm and nothing else: no input capacitance, no x10 setting, no bandwidth limit, so there is no probe ringing and no roll-off to see.
• No noise anywhere in the engine, so a flat line is perfectly flat and an FFT's floor is the window's own side lobes.
• No math channel, no persistence and no vertical quantization.

Common mistakes

Forgetting the ground clip. Without GND wired to the circuit's ground, both channels are measured against nothing in particular, which is as meaningless as a real probe left unclipped.

A trace that will not stand still: the trigger has no clean edge. Try the other channel as source, or set a level that the signal actually crosses.

Related

RC filter on the scope and RL filter on the scope are built around this part, and RC filter on the bench and 555 on the bench put it beside a multimeter on the same signal. Open them at /templates. See the bench instruments for the whole set, and the logic analyzer for digital buses.