Our FAQ answers frequently asked questions about oscilloscopes.
What Is an Oscilloscope?
An oscilloscope is an electronic measuring instrument used to display independent voltages in a two-dimensional coordinate system.
What does an oscilloscope do?
An oscilloscope displays an electrical signal over time. It generates a graph with time on the x-axis and voltage on the y-axis.
What can I adjust with the control panel?
You can adjust both the vertical and horizontal scaling using the control panel. This allows you to control the signal display, set trigger conditions, sampling rate, or select the operating mode for your measurement.
What does triggering mean on an oscilloscope?
A "trigger" is a starting event. Triggering tells the oscilloscope when to begin capturing a signal.
How Much Bandwidth Does an Oscilloscope Need?
Bandwidth is critical for accurate measurements. When analyzing analog signals, the oscilloscope’s specified bandwidth should be at least three times higher than the highest sine frequency.
For digital signal analysis, we recommend bandwidth five times greater than your highest clock frequency. System bandwidth refers to the combined bandwidth of the probe and oscilloscope. Analog bandwidth indicates the maximum frequency that the oscilloscope’s input stage can handle.
How Many Channels Does an Oscilloscope Need?
Many oscilloscopes can measure and display multiple signals simultaneously. Each signal is assigned to a channel. Common models offer 2 to 8 channels. A mixed-signal oscilloscope (MSO) adds a 16-channel logic analyzer for viewing and analyzing both analog and digital signals.
What Is the Sampling Rate of an Oscilloscope?
The sampling rate defines how many times per second your oscilloscope samples a signal (samples per second, S/s). The higher the sampling rate, the greater the resolution and the more accurate the signal display. "Waveform capture rate" refers to how fast the oscilloscope can capture waveforms (wfms/s). When using multiple channels, the sampling rate may decrease. Also, at longer time base settings, the sampling rate is limited by available memory depth.
How Is Memory Depth Calculated for an Oscilloscope?
To achieve a maximum sampling rate over a longer time span, a deep memory is required. The requirement is calculated using the formula: Memory depth = Record length * Sampling rate.
What is the record length of an oscilloscope?
An oscilloscope can only store a limited number of samples. The recording duration is inversely proportional to the sampling rate. Modern devices allow you to set the record length to suit your signal requirements.
What rise time should the oscilloscope have?
Your device should have a fast rise time to accurately capture signal transitions. Rise time (slew rate) describes the frequency range the oscilloscope can measure. The relationship between bandwidth and rise time is defined by a constant: Rise time = k / Bandwidth, with k between 0.35 and 0.45.
What does vertical resolution mean?
Vertical resolution indicates how accurately the A/D converter translates an input voltage into digital values. Typical values are 8 to 16 bits. Effective amplitude resolution can be enhanced through digital processing modes like High-Resolution (Hi-Res) mode.
What is vertical sensitivity?
Vertical sensitivity describes how weak signals are amplified for better display.
Using oscilloscope interfaces
Analyzing your results is as important as data transfer and documentation. Oscilloscopes support a variety of interfaces, such as PCI Express, GPIB, and USB. When purchasing, consider what connectivity options you need.
Expandability
Your oscilloscope should be ready for future measurement tasks. Some models support upgrades in channel count, bandwidth, and memory. Application-specific measurement functions and additional software, probes, and accessories can also be added.
Which Companies Manufacture Oscilloscopes?
Well-known oscilloscope manufacturers include:
- Keysight
- Tektronix
- Pico
- Rohde & Schwarz
- GW Instek
These brands offer a wide range of models with different designs, bandwidths, and application capabilities. You can find these and other brands in our online shop.
What software does my oscilloscope need?
Some manufacturers offer free software, while others provide advanced programmable tools. Standalone oscilloscopes often include demo programs; USB oscilloscopes require dedicated software. Software selection depends on form factor, manufacturer, measurement task, and product. Examples include NI, Pico, and Keysight applications.
How Do Analog and Digital Oscilloscopes Differ?
Oscilloscopes are generally classified as analog or digital. Digital oscilloscopes dominate the market due to key advantages like precise signal representation and multiple display/analysis modes.
The biggest benefit is in data storage and analysis. Results can easily be transferred to other devices like PCs. One limitation is the aliasing effect, where high frequencies are misrepresented as lower ones.
Analog devices tend to be bulkier and less accurate. Display issues can lead to misinterpreted results.
Other types include:
- CCD oscilloscopes use a charge-coupled device sensor and can measure in the GHz range with no sampling gap.
- Mixed-signal oscilloscopes (MSOs) combine analog and digital signal capture in one device.
- Waveform monitors are specialized for analog video signal analysis.
Benchtop and handheld oscilloscopes are also common. The terms "digital oscilloscope" and "handheld oscilloscope" are often used interchangeably. Benchtop units offer full features, while handhelds are compact with limited controls.
What Is the Structure of an Analog Oscilloscope?
An analog oscilloscope typically includes one or more analog inputs, a sawtooth generator, a power supply, and a cathode ray tube for displaying input signals.
What Is the Structure of a Digital Oscilloscope?
A digital oscilloscope generally includes:
- Probe
- Input channel(s)
- AC/DC coupling, attenuator, preamplifier
- Sampling/trigger unit
- A/D converter
- Processor
- Display monitor
Measuring Current with an Oscilloscope
AC current is typically measured using a "Rogowski coil" or Rogowski current sensor. These sensors are compact and robust, capable of measuring currents up to 100 kA.
DC current can be measured with a current clamp. These clamps usually handle up to 2 kA and can also measure AC current up to 100 MHz. They are sold as accessories.
Questions to Ask Before Buying an Oscilloscope
Which oscilloscope type do I need?
Depending on your measurement task, choose between a mixed-signal, analog, or digital oscilloscope. Your application largely determines the type.
How much bandwidth is required?
Determine the minimum bandwidth your tasks require. This value is essential for precise measurements.
How many channels do I need?
Basic signal analysis needs 2–4 channels. For fault analysis and troubleshooting, we recommend 8–16 channels.
Do I need digital inputs?
Depends on the task and device. Make sure to check for digital input requirements.
What sampling rate do I need?
Without sufficient sampling rate, signals cannot be accurately displayed. As a rule of thumb: Sampling rate should be at least twice the signal frequency.
What memory depth do I need?
The deeper the memory, the more detailed the measurement. If you need to record for long durations, a larger memory is necessary.
Do I need accessories like current clamps or probes?
These can support your task. Decide whether you need active/passive probes or a current transformer.
Do I need interfaces? If yes, which ones?
Buying Oscilloscopes for SMEs, Enterprises, and Professionals
Oscilloscopes are a major investment for SMEs and independent professionals. The factors listed above affect price and usability.
Entry-level models with low bandwidth and basic functions are more affordable, but only suitable for simple measurements. Contact us to discuss your measurement task—we’ll help you choose the best model.
How to Get an Oscilloscope Recommendation
A suitable recommendation requires defined requirements. Don’t choose alone—consult with our independent experts.
At dataTec, our team offers tailored advice to help you find the ideal oscilloscope for your measurement needs, saving you time and effort.
