How to use an oscilloscope to measure the voltage regulation value of a voltage regulator tube

　　Zener diode (also called Zener diode) works by utilizing the characteristics of the PN junction when it is broken down. Under a certain reverse voltage, the Zener diode is broken down. After breakdown, the voltage across it basically remains at a stable value. At this time, changing the current in the diode will not affect the voltage across the diode. That is, the reverse breakdown voltage of the diode does not change with the change of the reverse current. This is the voltage stabilizing characteristic of the Zener diode. The test circuit is as shown in the figure.

　　Test method: Adjust the oscilloscope to normal working status, set the input coupling switch of the two channels to "DC", and adjust the two vertical displacement (Yl, Y2) knobs respectively to make the two baselines coincide and align with a certain horizontal scale line at the bottom. . The "Y-axis attenuation" position of the two channels should be consistent. Set the input coupling switch to the "DC" position. Adjust the output voltage of the regulated power supply. Observe the changes of Ul and U2 on the oscilloscope screen. At this time, as the UI increases. U2 should also be increased accordingly.

　　Continue to add UI. Until U2 no longer rises, then measure the value of U2 according to the method of measuring DC voltage, which is the voltage stabilization value VD of the Zener diode.