Oscilloscope

Oscilloscopes display voltage signals as they vary over time. It is possible to determine the wave-form, frequency, amplitude and noise level of the input signals. Multiple inputs allow for measuring phase differences between signals. Thus, oscilloscopes are very useful to debug electronic circuits.

General Notes on Operation

This section is for notes on general operation, as well as tips and tricks for new and intermediate users.

X1/X10 attenuation

For new and intermediate users, all measurements should be taken in the X10 attenuation mode of your Probes and Oscilloscope. This protects the oscilloscope from accidental damage.

If you are getting implausible readings, check that probe and oscilloscope are set to X10 - for all connected channels.

Display

The oscilloscope screen consists of a grid of divisions and displays the measured electrical signals as an X-Y plot. The horizontal X-Axis represents the time and the vertical Y-Axis represents the voltage.

Common Mode Noise

A problem when measuring mains-powered devices is common mode noise (also called common mode interference, Gleichtaktstörung). German-speaking readers should watch Die größte Seuche der Elektrotechnik, providing an explanation of the phenomenon for beginners.

Common Mode Noise is mostly found in switching power supplies. Most modern AC-DC adapters such as laptop/phone chargers, 12V wall warts and more are so-called "switching" power supplies. Common mode noise emerges because it's impossible to perfectly seperate the primary (input) and secondary (output) sides of a switching power supply, allowing a small current to leak across it - and this leakage current can interfere with measurements or even destroy sensitive devices.

You can measure this - Take a multimeter in AC Voltage mode, a cheap switching power supply, and measure the voltage from the positive output terminal to something grounded, such as your body. For most switching power supplies, the multimeter will display between 20 and 200 Volts. This is common mode noise. Its current capacity is very low, less than 0.5 mA in most cases, so is only dangerous for sensitive electronics and measurement results, not humans.

It can help to connect the probe ground clip to a GND close to where you are measuring, or just to try a different GND connection around your board.

You can also try procuring a power supply that doesn't output any common mode noise.

Only take the following steps if your measurements are bogus, and you have confirmed your power supply is causing common mode noise. If you do the following steps and the oscilloscopes' ground clips touch a power rail, you will create a short circuit with destructive implications, a unnessecary risk for most common measurements.

To more radically dissipate common mode noise, you need to ground the output of your switching power supply - e.g. connect the output GND to the power plug PE.

For most measurements it is enough to do this locally, as the oscilloscope probe ground clips are on ground potential, but sometimes it might be nessecary to add a extra cable to connect the secondary (output) GND of your power supply to the grounding points around the E-Bench. This is more risky and should only be done if you are encountering high voltage interference on your measurements.

Siglent SDS814X HD

MachineInfoBox Siglent SDS814X HD

Type:	Oscilloscope
Location:	Electronics Area
Access Requirements:	Oscilloscope Introduction
Status:	Working
Manual:	siglent.eu
Tutors:	Johannes

The Siglent SDS814X HD is a four-channel digital storage oscilloscope featuring 12-bit vertical resolution and a 100 MHz bandwidth, designed for electronics development, debugging, and education.

Thanks to its high resolution, the SDS800X HD series provides improved signal fidelity compared to traditional 8-bit oscilloscopes, making it especially suitable for low-noise and mixed-signal measurements.

Key Features

4 analog input channels
12-bit ADC resolution
100 MHz bandwidth
High-resolution capacitive touch display
Serial bus decoding and triggering
SCPI remote control support

Available Probes

Siglent PP510

This Oscilloscope came with 4 Siglent PP510 probes. You can find the user guide on siglentna.com

Serial Bus Decoding

The oscilloscope supports decoding and triggering for common serial protocols:

I²C
SPI
UART
CAN
LIN

This allows direct analysis of digital communication signals without additional tools.

Controls & Connectivity

capacitive touch screen for intuitive operation
USB keyboard and mouse support
two USB-A ports for input devices and storage media
RJ45 Ethernet port for network connectivity
remote control via web browser

Automation & Programming

The SDS814X HD is fully programmable using SCPI commands.

This enables automated measurements and data acquisition, for example using Python.

A detailed programming guide is available from Siglent.

Usage Notes

suitable for analog and digital signal analysis
ideal for embedded systems, microcontroller projects, and bus debugging
not intended for high-frequency RF measurements beyond its bandwidth