The circuit structure of the probe accessory:
● There will be a pair of damping resistors (usually 82ohm) at the tip of the probe attachment. The function of this damping resistor is to eliminate the resonance effect of the inductance at the tip of the probe attachment;
● Behind the probe tip part is a 25Kohm resistor, which determines the input impedance of the probe (DC input impedance is resistance: single-ended 25Kohm, differential 50Kohm), this resistance makes the power of the measured signal transmitted to the probe amplifier part very high. small, so that it will not have a great impact on the measured signal.
The 3.25Kohm resistor is followed by the coaxial transmission line, which is responsible for transmitting the small signal to the amplifier. The length of this transmission line can be very long or very short, and an attenuator or a coupling capacitor can be added in the middle.
● The coaxial transmission line is connected to the amplifier, which is 50ohm matched (differential 100ohm matched).