Measuring quartz crystal with multimeter and its working principle
The measurement of quartz crystal oscillation generally requires the use of instruments, and there are many quality parameter items involved. If you want to judge the quality of a quartz crystal, you can use a multimeter for measurement.
When measuring with a multimeter, place the multimeter in the Rx1k range and first measure the two ends of the quartz crystal. When measuring a normal quartz crystal in resistance mode, its resistance value should be infinite, and the pointer of the meter should not swing. If the pointer of the meter head swings and the resistance value is very small, it indicates that the quartz crystal being measured has been damaged. If further judgment is required, measurements can be taken along the line shown in the following figure.
When the A and B terminals are connected to a quartz crystal, the multimeter voltage range indicates approximately 0.75V. After connecting the quartz crystal, the circuit should vibrate and the voltage should increase, usually around 1.26V. If the above requirements are met, it indicates that the tested quartz crystal can be used. If there is no change in voltage indication after connecting the quartz crystal, it indicates that the tested quartz crystal has failed and has no practical value.
Common faults and maintenance methods of multimeters:
When the probe is short circuited, the pointer cannot be adjusted to zero or the pointer swings back and forth unstably
(1) Replace with a new battery of the same model;
(2) Replace the series resistor;
(3) Adjust the socket spring to ensure good contact, and remove the oxide layer on the probe plug and socket;
(4) Clean the switch contacts of the multimeter with alcohol and calibrate the contact distance between the moving contacts and the stationary contacts;
(5) Use tweezers to press down the moving contact piece in the middle of the zero potentiometer to ensure good contact with the static contact resistance wire;
The resistance range is not connected or the error is too large
(1) Replace the resistor with the same resistance and power;
(2) Wipe and repair poor contact areas with alcohol;
(3) Replace the shunt resistor of this gear;
(4) Replace with a new battery of the same model;
