What are the indicators that must be paid attention to when selecting Tektronix oscilloscope probes?

Tektronix probes ensure the highest signal fidelity from the device under test to the oscilloscope. With more than 100 probes to choose from, all designed to work perfectly with Tektronix's industry-leading oscilloscopes, there is always a probe that can meet your specific test application needs.

How to choose the right probe? First, consider the signal you plan to measure and choose the right probe. Do you need to measure voltage, current, or both? What is the signal frequency? How large is the signal amplitude? Is the source impedance of the device under test high or low? Do you need to measure the signal differentially? By answering these questions, you can choose the best probing solution from the many probe types available at Tektronix. Antai Test recommends considering the following five points:

1. Bandwidth

The probe bandwidth you choose should match the bandwidth of the Tektronix oscilloscope you will be using. A good rule of thumb is that the oscilloscope and probe bandwidth should be three to five times the highest signal frequency of interest. It is also important to consider the bandwidth of the signal rise time. At frequencies above 500 MHz, active probes generally provide better small signal performance.

2. Probe load

Ideally, the probe you choose should have as little effect as possible on the signal being measured. The value of the source impedance of the device being measured can significantly affect the net effect of any probe loading. For example, the loading effect of a common high impedance 10X passive probe is almost unnoticeable when the source impedance is low, because the high impedance in parallel with the low impedance does not introduce any significant change in the total impedance. Passive probes are an excellent low-cost general-purpose solution. However, higher bandwidth signals behave significantly differently when the source impedance is high. Active single-ended or differential probes are better choices when the source impedance is high.

3. Voltage or current amplitude

Probe selection varies significantly based on signal amplitude and type. Obviously, current probes are used to perform current measurements. However, it is important to consider whether an AC current probe or an AC/DC current probe is required. Additionally, current probes are divided into solid core toroidal designs and split core designs. Split core designs offer the important ease-of-use advantage of clamping around the wire without having to desolder and resolder, as is required with solid core toroidal current probes.

Voltage probes are available in a variety of configurations, including small signal passive probes, active probes, differential probes, high voltage differential probes, and high voltage passive probes. When selecting a probe, consider the amplitude and whether floating measurements are required.

4. Probe tip connection

Most probes come with a range of standard accessories. These accessories typically include a ground lead clip to connect the probe, a compensation adjustment tool, and one or more probe tip accessories to assist in connecting the probe to various test points. Probes designed for specific application areas, such as probing surface mount devices, may include additional probe tip adapters in addition to the standard accessory kit. In addition, a variety of specialized accessories can be provided as options for the probe.

5. Oscilloscope interface

Depending on the performance level of the oscilloscope, Tektronix oscilloscopes are equipped with different oscilloscope-to-probe interfaces, including standard BNC connectors used by basic oscilloscopes, and smart interfaces such as TekVPITM and TekConnect®. Smart interfaces provide many unique features such as AutoZero, on-screen menus using the Probe Menu Button, and more. Depending on the interface used, an adapter may be required to use an existing Tektronix probe.