Methods for detecting the quality of capacitors using a multimeter
Capacitors, usually abbreviated as the ability to store charge, are represented by the letter C. Definition 1: A capacitor, as the name implies, is a "container for electricity" and is a device for storing charge. English name: capacitor. Capacitors are one of the electronic components widely used in electronic devices and are widely applied in aspects such as isolating direct current and passing alternating current, coupling, bypassing, filtering, tuning circuits, energy conversion, and control in circuits. Definition 2: For a capacitor, any two conductors (including wires) that are insulated from each other and are very close together form a capacitor.
Capacitance is different from a capacitor. Capacitance is a basic physical quantity, with the symbol C and the unit F (farad).
With the rapid development of electronic information technology, digital electronic products are being updated at an increasingly fast pace. The production and sales volume of consumer electronic products mainly represented by flat-panel TVs (LCD and PDP), laptops, digital cameras, etc. continue to grow, driving the growth of the capacitor industry. It also drives the development of related materials and equipment industries, and China has become a major capacitor producer globally.
Detection of fixed capacitors
A. Detection of small capacitors below 10pF
Since the capacitance of fixed capacitors below 10PF is too small, when measured with a multimeter, only the presence of leakage, internal short circuit or breakdown can be qualitatively checked. When measuring, select the R×10k gear of the multimeter, and connect the two test leads to the two pins of the capacitor arbitrarily. The resistance value should be infinite. If the measured resistance value (the pointer swings to the right) is zero, it indicates that the capacitor is damaged by leakage or internally broken down.
B. Detect whether the fixed capacitors between 10PF and 0.01μF have a charging phenomenon, and then judge their quality.
Select the R×1k gear of the multimeter. The β values of the two triodes are both above 100, and the penetration current should be small. Silicon triodes of models such as 3DG6 can be selected to form a composite tube. Connect the red and black test leads of the multimeter to the emitter e and the collector c of the composite tube respectively. Due to the amplification effect of the composite triode, the charging and discharging process of the measured capacitor is amplified, and the swing amplitude of the pointer of the multimeter is increased, making it easier to observe. It should be noted that during the testing operation, especially when measuring capacitors with a small capacity, the pins of the measured capacitor should be repeatedly switched to contact points A and B to clearly see the swing of the pointer of the multimeter.
C. For fixed capacitors above 0.01μF, the R×10k gear of the multimeter can be used to directly test whether the capacitor has a charging process, internal short circuit or leakage, and the capacitance of the capacitor can be estimated according to the amplitude of the pointer swinging to the right.
