Resources
Q
What is LCR digital bridge?
It is a traditional saying. The earliest LCR test is a real bridge balance test method, which is still used today.
Q
As a new user, how to choose a digital bridge?
(1) The first thing is to look at the test accuracy of the instrument.
(2) Look at the test frequency of the instrument.
(3) Look at the test level of the instrument.
Others depend on the specific situation of the customer, or you can consult Tonghui Company for technical advice based on the actual situation of the customer.
Q
Does different frequencies have an impact on component testing?
Yes. For details, please refer to the test signal frequency signal correlation in the article 5. Impedance measurement basics in the technical support of Tonghui website.
Q
Does the voltage have an impact on the component test?
Yes, please refer to the technical support of Tonghui website for details.
Q
How to choose test voltage and frequency?
(1) According to the actual application of the test piece.
(2)According to relevant product standards.
(3)According to customer's own requirements.
Q
For a known "capacitance", what test condition should the customer choose?
(1) Capacitors less than 100pF are measured with 1MHZ frequency, and for medium capacitance (1000pF-10uF) with 1KHZ, 10KHZ, 100KHZ. The national standard for testing medium capacitance is 1KHZ. Electrolysis type such as aluminum electrolysis, tantalum electrolysis, etc. use 100HZ or 120HZ.
(2) From the perspective of level, most capacitors are not sensitive to the level, and the test of different levels does not change much, but some capacitors with large dielectric constant are very sensitive to the level, and the level should be selected carefully.
Q
What is loss D, quality factor Q?
D and Q are the reciprocal of each other. The calculation method is the ratio of the active power PR (resistor energy consumption) of the device under test to the reactive power PC (capacitor energy storage) or PL (inductor energy storage). The series and parallel equivalent circuits are calculated using the following formula: =Rs/|Xs|,D=|Xp|/Rp, the values of D and Q have nothing to do with the equivalent way.
Q
How to choose series and parallel test parameters?
a. It can be determined by the variability of the loss factor at two different test frequencies. If the frequency increases and the loss increases, the series equivalent circuit should be used. If the frequency increases and the loss decreases, the parallel equivalent circuit should be selected. Circuit. For inductors, the situation is just the opposite of capacitors. In practice, the D of the device cannot be completely proportional to the frequency. It may have components in parallel or in series, depending on which component is dominant. b. Determined according to the final use of the component. If it is used for signal coupling capacitor, it is best to choose the series connection mode, and use the parallel equivalent circuit for bypass or parallel resonance. C. It is customary to say that low-impedance components are connected in series. From a numerical point of view, the impedance must be connected in series if the impedance is less than 100 ohms. If the impedance is greater than 10 kilohms, it must be connected in parallel.
Q
What is equivalent series resistance Rs \ parallel resistance Rp?
Any device under test can be equivalent to a series circuit or parallel circuit. The series resistance Rs is the resistance part of the series equivalent circuit, and Rs is also called ESR. The parallel resistance Rp is the resistance part of the parallel equivalent circuit. Rp is also called EPR.
Q
How to choose the test speed?
Generally speaking, the test speed is at the expense of test accuracy: the faster the speed, the worse the accuracy, the poorer reading stability, and the less effective digits. If you want to test the accuracy, generally choose the slow speed, consider the test speed and test accuracy, choose the medium speed.
Q
Why should the instrument be cleared?
Because 1. Due to the drift of the instrument itself, some stray components will be superimposed, such as contact resistance, inductance, parallel capacitance, etc., if it is not cleared, there will be errors.
2. Short-circuit clearing is more effective for low-impedance devices, and open-circuit clearing is more effective for high-impedance devices.
Q
What is load calibration, and what should be paid attention to for load calibration?
Load calibration is an advanced instrument calibration method, which enables the instrument to measure components on the basis of higher accuracy than the original instrument. It is mainly used in the following two situations: 1. When there are more accurate components and need to be corrected Components of the same specification can be measured with higher accuracy. 2. Unify the test data of all LCR digital bridges on site. 3. Using load calibration can make the instrument test with higher accuracy.
Q
What is the difference between sweep frequency and dot frequency reset?
1. The frequency sweep is generally for the tested component with more actual test frequency points, and the point frequency reset is generally for the tested component with only one frequency point.
2. However, it will take a long time for the sweep frequency to be cleared.
Q
What is the difference between the display range and the accuracy range of the measurement?
The display range of the measurement is generally larger than the accuracy range. For the specific accuracy calculation, please refer to the relevant technical data of Tonghui. .
