Your first oscilloscope for ESP32 projects: see the rail and the signal

Your ESP32 resets, the sensor drops out, and the multimeter still shows a perfectly respectable voltage. Time to see what happened between the readings. Choose the RIGOL DHO804 for USB-C power and HDMI output, or the SIGLENT SDS804X HD for its optional digital-channel expansion. Both put four analog channels on the bench.

Sources: research-based picks from the makers’ manuals and datasheets, checked November 1, 2026.

What a scope adds to your meter

Keep the meter. It answers the steady questions: voltage, continuity and resistance. A scope adds a picture of voltage over time, so you can examine a supply rail alongside a sensor or control signal. That makes it a useful next tool after your first electronics bench is up and running.

Start with low-voltage board signals. These picks are for rails and control lines, rather than looking directly at the ESP32’s Wi-Fi radio. Give each channel a specific question: what does this line do, and when does it change relative to the other one?

Two scopes, two bench jobs

Pick	Analog inputs	Bench connections	Choose it for
RIGOL DHO804	4 channels, 70 MHz, 12-bit ADC	USB host/device, LAN, HDMI output; USB-C power	A scope beside your existing desk display
SIGLENT SDS804X HD	4 channels, 70 MHz, 12-bit ADC	USB host/device and LAN	An analog bench with an optional digital-expansion route

The RIGOL model table identifies DHO804 as the four-channel 70 MHz version. Its HDMI output is the useful difference if you want a larger view of the trace. Use the supplied power adapter and earth lead as the manual directs.

Choose SIGLENT SDS804X HD if the maker’s optional SLA1016 logic-analyzer expansion interests you. The base scope includes passive probes, one per channel; the digital accessory is a separate addition. You can start with analog measurements and decide on that expansion later.

Both specify a nominal 12-bit ADC. Treat that as the converter specification, not a complete accuracy rating. For your first session, a correctly grounded, compensated probe matters much more than collecting specification-sheet trophies.

More enabled channels share the acquisition resources

Read the channel count beside the headline sample rate. These are maker-rated maximums, with the relevant inputs enabled:

Scope	One channel	Two channels	Four channels
RIGOL DHO804	1.25 GSa/s	625 MSa/s	312.5 MSa/s
SIGLENT SDS804X HD	2 GSa/s	1 GSa/s	500 MSa/s

RIGOL also specifies 312.5 MSa/s with three channels enabled. Its maximum memory depths are 25 Mpts with one channel, 10 Mpts with two, and 5 Mpts with three or four. SIGLENT’s 70/100 MHz models specify 50 Mpts per channel in one-channel mode, 25 Mpts in two-channel mode and 10 Mpts in four-channel mode. See the RIGOL datasheet and SIGLENT datasheet for the acquisition tables.

Enable the channels you need for the question in front of you. When you add another signal, check the acquisition settings again. That habit beats assuming the biggest number on the box applies to every trace at once.

Ground first, then connect

Keep this first session to low-voltage circuits, with probe ground clips on the circuit’s grounded reference, never a powered rail. Connect DHO804’s supplied earth lead before any input/output connections; keep SIGLENT’s protective mains earth intact. These are non-isolated bench inputs: USB-C or power-bank operation does not make the RIGOL an isolated scope. Follow the grounding instructions in the RIGOL manual or SIGLENT manual.

Your first win: compensate a passive probe

Before chasing an ESP32 fault, use the scope’s own compensation output. You get a known signal and a useful introduction to the controls.

1. Connect the passive probe’s BNC connector to an analog input.
2. Match the channel’s probe ratio to the attenuation selected on the probe.
3. Put the ground clip on the compensation ground terminal and the tip on the compensation signal output.
4. Use Auto on RIGOL or Auto Setup on SIGLENT to display the signal.
5. Adjust the probe’s compensation with the specified tool until the square-wave top is flat, rather than rounded or overshooting. Repeat for the other probes you’ll use.

SIGLENT documents a 0–3 V, 1 kHz compensation signal. The expected period is simple arithmetic:

period = 1 / frequency
       = 1 / 1000 seconds
       = 1 ms

That is a calculated expectation for the documented output. Use it to connect the timebase to what you see on screen; the compensation adjustment is about getting the waveform shape right.

Next: a rail, then a control signal

For a project to investigate, the first ESPHome sensor build gives you a documented board pinout and sensor connections. Identify the board’s ground and the signal you want before attaching a probe.

Start with DC coupling on a known low-voltage rail. Set the vertical scale around its documented voltage and adjust the timebase for the event you want to inspect. Add a control signal on another channel when you want to compare timing.

For an event that happens once, use an edge trigger and Single acquisition: the scope waits for the trigger condition, captures, then stops. Save the waveform and settings with a short note about the probe ratio and connection points. You now have something concrete to compare when you change the circuit.

Choose the RIGOL for USB-C and HDMI, or the SIGLENT for the optional digital route. Then spend your first session learning the probe and trigger controls. The best trace is the one that answers your question.