Introduction to four common oscilloscope probes
The oscilloscope probe is a test instrument that everyone is familiar with, but there is no way to test an oscilloscope without a probe. The oscilloscope probe is indeed an indispensable member of the oscilloscope family. The performance of the probe will have a direct impact on the final test results. There are four common oscilloscope probes: passive probes, active probes, differential probes and current probes. Let's give you some brief introduction below.
1. Passive probe
Attenuated passive voltage probes are the most commonly used probes. Common passive probe bandwidths are below 500MHz. Most mid- to low-end oscilloscopes come standard with two or four passive probes. It is a very convenient and relatively cheap probe.
High voltage probes and transmission line probes also belong to the category of passive probes.
2. Active probe
Active probes have high input impedance and can achieve very high bandwidth. The disadvantages of active probes are their high cost, large size, and the need for a power supply.
3. Differential probe
Differential probes are divided into active differential probes and high-voltage differential probes. When testing high-speed signals, especially differential signals, only corresponding active differential probes can be used for testing. Active differential probes have the characteristics of low loading effect, higher signal fidelity, high dynamic range and minimal temperature drift. In the testing of many high-voltage signals, high-voltage differential probes are generally used for testing.
4. Current probe
When using an oscilloscope to test current, a current probe is used. Commonly used current probes are made using the Hall principle. It obtains the current signal by measuring changes in the magnetic field around the circuit.
When selecting a current probe, you should pay attention to several main parameters: the current size of the object to be measured, current frequency, AC or DC, shape and size of the jaw, power supply method, interface form, etc.
In the actual testing process, we should choose the appropriate oscilloscope probe. Only in this way can we get accurate test results.
