An oscilloscope draws a graph of an electrical signal over time. Let's
walk through what the screen is showing you.
Mystery Signal #1
Channel
Vertical
−
+
V / Div
1.00 V
−
+
Position
0.00 div
Coupling
Horizontal
−
+
Time / Div
200 µs
−
+
Position
0.00 div
Trigger
−
+
Level
0.00 V
Edge
Mode
Cursors
T1—T2—ΔT—1/ΔT—
V1—V2—ΔV—
Measurements
Each slot displays one live measurement in the scope footer.
Tap a slot to assign, change, or clear its measurement.
When CH2 is on, the CH1/CH2 chip on each slot picks which
trace that slot measures.
Function Generator
Configure the signal source feeding the oscilloscope.
Changes take effect immediately on the scope display.
Waveform
Select a Mystery Signal
1
Frequency
1.00 kHz
Amplitude
2.00 V
Duty Cycle
50%
Sawtooth Direction
DC Offset
0.00 V
Capture
Save the current oscilloscope display (including any active measurements).
Probe Attenuation
Tell the scope what kind of probe is attached. A 10× probe divides the signal by ten on its way in, so each division covers ten times more volts — the trace shrinks until you rescale V/Div, and the V/Div readout shows the probe-corrected value. Measurements and cursors always read true probe-tip volts.
Quick Reference
This page explains the most important controls and measurements.
Use it while you are working with the oscilloscope.
Types of waveforms
The shape of a signal tells you what it is doing in time.
These are the six options the function generator can produce.
Sine
A smooth oscillation at a single frequency.
Example: Audio tones, AC wall power, natural vibrations.
Square
Switches sharply between two voltage levels.
The duty cycle controls how long the signal stays high in each cycle.
Example: Digital clocks, PWM motor control, logic signals.
Triangle
Linear rise followed by a linear fall at the same rate.
Example: Test signals, sweeping voltages, audio synthesis.
Sawtooth
A linear ramp that snaps back at the end of each cycle.
The FORWARD / REVERSE buttons flip which side is the ramp and which is the snap.
Example: Old TV and oscilloscope sweeps, analog synthesizers.
DC
A constant voltage with no change over time.
Appears as a flat horizontal line on the scope.
Example: Battery voltage, a steady power supply rail.
Mystery
A real-world signal for you to identify using the scope.
Example: Real signals from sensors and circuits, ordered from basic to advanced. The library includes 120 VAC line voltage, rectified DC, diode and capacitor and inductor signatures, a 555 timer, servo pulses, switch bounce, a heartbeat sensor, encoder pulses, UART data, PWM motor drive, and faulty signals to troubleshoot.
Waveform properties
These are the numbers used to describe any repeating signal.
Amplitude
Peak voltage measured from zero to the crest of the waveform. Usually in volts (V) or millivolts (mV).
Peak-to-peak Vpp
Total swing from the lowest point to the highest. For a centered wave, Vpp = 2 × amplitude.
Period T
Time for one complete cycle. Measured in seconds, milliseconds (ms), or microseconds (µs).
Frequency f
Number of cycles per second, measured in hertz (Hz) or kilohertz (kHz). f = 1 / T.
Duty cycle
For square and pulse waves, the percent of each period the signal stays high.
Phase
Where in the cycle the waveform starts, measured in degrees.
DC offset
A constant voltage that shifts the entire waveform up or down from zero.
Input coupling
Coupling controls how the probe input is connected to the
rest of the scope. Pick it based on what part of the
signal you want to see.
DC coupling
Passes the entire signal, including any constant offset. The standard choice for most work.
Use when: You are doing most everyday measurements.
AC coupling
Removes any constant voltage so you only see the changing part.
Use when: You have a small signal riding on a large DC voltage (example: an audio signal on a 5 V power rail).
GND coupling
Disconnects the probe input and shows the zero-volt reference line.
Use when: You need to find where 0 V is on the screen before taking a measurement.
Triggers
Triggering tells the scope when to start drawing each sweep,
so a repeating waveform appears stable instead of drifting
across the screen.
Trigger level
The voltage the signal must cross to start a new sweep. Shown as an orange flag at the right edge of the display.
Use when: Your waveform is drifting across the screen.
Edge
Rising captures upward crossings. Falling captures downward crossings. Set with the RISING / FALLING buttons in the Trigger section.
Rising edge ↑
Falling edge ↓
Auto mode
Sweeps continuously, even when no trigger event occurs. Something is always on screen.
Use when: You want to see the signal right away without waiting.
Normal mode
Sweeps only when the trigger condition is met. The display holds the last good trace if no trigger occurs.
Use when: You want the scope to wait for a specific event.
Single mode
Captures one sweep, then holds the trace until armed again.
Use when: You want to catch a one-time event, like a switch press.
FORCE
Momentary press. Captures one sweep immediately, ignoring the trigger condition. Use it when Normal or Single mode is waiting on a trigger that may not arrive, or when the scope is stopped and you want to see what is happening right now.
Tip
Start in AUTO mode. Switch to NORMAL when you want the scope to wait for a specific event.
Common problem
Waveform will not stay still? Try adjusting the Trigger Level so it sits inside the signal, or switch from AUTO to NORMAL.
Taking measurements
The scope can compute readouts directly from the displayed
sweep. Assign any of them to one of the four MEAS slots.
Best for clean, repeating signals where you want a fast,
stable readout.
Probe setting
The PROBE button tells the scope what probe is attached (1×, 10×, or 100×). A 10× probe divides the signal on its way in, so each division covers ten times more volts — readings stay in true probe-tip volts. If your trace suddenly looks ten times too small, check the probe setting first. High-voltage signals like the 120 VAC line are exactly what the 10× and 100× probes are for.
Most useful
Start with these. You will use them most often.
Voltage
Vpp
Peak-to-peak voltage from the lowest to the highest point.
Vmax
Highest single voltage in the displayed signal.
Vmin
Lowest single voltage in the displayed signal.
Vavg
Average voltage across the displayed sweep. About zero for symmetric AC. Equal to the DC offset otherwise.
Time
Frequency
Cycles per second (Hz), calculated from the measured period.
Period
Time for one complete cycle. Measured between matching points on the waveform.
Pulse shape
+Width
Positive pulse width: time the signal stays above the 50% level in one cycle.
Duty %
Duty cycle for square waves: percent of the period the signal is high.
See More Measurements
Useful for more advanced work and for analyzing signal
quality on sharp edges.
Voltage
Vrms
RMS voltage: a way of measuring the "effective" voltage of a changing signal. For a pure sine wave, Vrms ≈ 0.707 × amplitude. Under AC coupling the scope reports AC-only RMS, matching a true-RMS multimeter.
Pulse shape
Rise
Time the signal takes to climb from 10% to 90% of its full swing on a rising edge. A measure of how sharp the transition is.
Fall
Time the signal takes to drop from 90% to 10% of its full swing on a falling edge.
–Width
Negative pulse width: time the signal stays below the 50% level in one cycle.
+Duty %
General positive duty cycle, computed as +Width / Period × 100%.
–Duty %
General negative duty cycle, computed as –Width / Period × 100%.
Signal quality
Overshoot+
How far the signal rises above its steady high level after a sharp transition, as a percent of the full swing.
Overshoot–
How far the signal drops below its steady low level after a sharp transition, as a percent of the full swing.
Crest
Crest factor: how "peaky" or spiky the signal is compared to its average power. Calculated as Vpeak / Vrms. A pure sine wave has a crest factor near 1.41. Sharper, spikier signals have higher values.
Using cursors
Press CURSOR, then switch on TIME
(two vertical lines), VOLTAGE (two horizontal
lines), or both. Drag each line directly on the trace; the
scope reads the difference between the pair. Use cursors
for one-shot events, partial cycles, or any value the
automatic list does not include.
Time cursors
Two vertical lines. Δt reads the time between them and 1/Δt converts that into a frequency. Useful for pulse width, time between two events, or partial cycles.
Voltage cursors
Two horizontal lines. ΔV reads the voltage difference between them. Useful for measuring a step, a gap between features, or any voltage the automatic list does not cover.
Pro tip
Use cursors when automatic measurements do not give you what you need. Example: measuring only part of a waveform, or the gap between two pulses.
Two channels & more tools
Some signals let you attach a second probe to a related
point in the circuit — usually the input that produces
the output you see on CH1.
CH2
A Channel selector appears in the Vertical section whenever the signal offers a second probe point. One press switches a channel on and gives it the V/Div and Position knobs; pressing the selected channel again hides its trace (one trace always stays on). Trigger and cursors always read CH1; measurements read CH1 unless you flip a slot's CH1/CH2 chip in the MEASURE panel.
Use when: You want to compare a circuit's input against its output — the square wave driving an RC against the capacitor's charge curve.
Share Setup
The masthead link copies a URL that reopens this page with your exact generator and scope settings — handy for saving work or sending a setup to someone else.