Capacitance meter is a device for measuring electric capacitance , mainly used to measure the capacitance of discrete capacitors . Depending on the complexity of the measuring device, it can only measure capacitance or measure a number of other parameters, such as leakage , and inductance . In measurements, in most cases, the capacitor should be disconnected from the electric circuit ; ESR is usually measured without disconnecting from the circuit.
Simple measurements without a real capacity meter
Some checks can be performed without special equipment, such as aluminum capacitors, which have a large capacity and low leakage. The multimeter can detect a short circuit (very low resistance) or large leaks (large resistance, but less than it should be; an ideal capacitor has infinite DC resistance). The tough idea of measuring capacitance is to measure it with an analog multimeter in the high resistance range. When the first contact is already connected, then when the second contact is connected, there will be a “discharge” from large to low resistance, this can continue indefinitely. The amplitude of the "discharge" is an indicator of capacity. Interpretation of the results requires some experience, or a comparison with a working capacitor, and depends on the specific measuring instrument and the range used.
Digital Voltmeters
Most digital voltmeters have a capacitance measurement function. Usually they work by charging and discharging the tested capacitor with a known current and its increase rate. The lower the speed, the larger the capacity. Typically, multimeters can measure capacities ranging from nanofarads to several hundred microfarads, but wider ranges are not unusual.
- Rotary Capacitance Measurement with a Digital Multimeter
C min = 29 pF
C = 269 pF
C max = 520 pF
See also
- Immitance Meter