Oscilloscope probe measurement principle

When making electronics, we inevitably use a variety of test instruments, and one of the more commonly used ones is the oscilloscope. When using an oscilloscope, we use probes to measure physical quantities such as time, frequency, and voltage values. But have you ever thought about how the probe measures these physical quantities?

The probe uses the high impedance characteristic to ensure that the circuit is not interfered by the measurement part, but sometimes we need to use low impedance testing methods to measure certain circuits. For example, for a RF output circuit with 50 ohm impedance, for a machine with 50 ohm impedance measurement function, this is just a matter of pressing a button; but for an ordinary oscilloscope, the probe is not suitable for measurement at this time. You need to use a BNC tee with a 50 ohm end resistor to match it, and connect the other end directly to the 50 ohm output.

For many enthusiasts, these are very simple questions that they rarely think about. In fact, the measuring instruments around us are all the same. We rarely pay attention to their principles in daily use, but do you want to use them well? It takes some thinking!