Capacitance testers are used to test the capabilities and performance of capacitors, specifically, their ability to hold or store an electrical charge. Capacitance testing is vital to finding leaking capacitors which may reduce the effectiveness of an overall circuit and result in the electrical failure of a device. A capacitance tester can also be used to perform a capacitance continuity test. Capacitors are electronic components that are used widely in many industries, including signal processing and power supply applications. They are especially useful in computer motherboards for managing the on and off switching necessary for processing binary code. Capacitance is measured in units called farads, where a 1 farad capacitor would store one coulomb of charge at one volt. However, most capacitors are measured in microfarads.
Capacitance testers can be tabletop or handheld, portable devices with test leads that attach to a circuit to evaluate the quality of a capacitor or condenser. Capacitance testers identify when a capacitor is weak or leaking, or whether a capacitor is open and not storing a charge, or is shorted out. A capacitance meter is a type of tester that reads the capacitor’s charge and may also monitor other impedance measurements including resistance and inductance. Capacitance testers measure different ranges of charge; a typical handheld device may range from 200pF to 20mF.
Capacitance testers may also come with a probe for testing capacitors in environments where the circuits are difficult to reach with test leads, or where materials being tested are wet or sticky. Capacitance testers that come with probes are also used in high-temperature or high-corrosion environments. A capacitance probe is usually constructed of stainless steel and coated with Teflon or polyethylene for insulation. Teflon is a registered trademark of DuPont. For high-temperature applications, a capacitance probe may be made of ceramic materials.
Capacitance testers bear marks from various national and international approval organizations. For example, the European Union (EU) requires CE marks for all electric and electronic equipment that will be sold, or put into service for the first time anywhere in the European community. Capacitance testers that have a CSA Mark have been tested by the Canadian Standards Association (CSA) and meet applicable standards for safety and/or performance. These standards are written and administered by organizations such as the American National Standards Institute (ANSI), Underwriters Laboratories (UL), and CSA International. The International Electrotechnical Commission (IEC) also prepares and publishes standards for capacitance testers.