Fechar
A _____ is a device that can store and release an electrical charge over a period of time.
A basic capacitor consists of two metal plates separated by a thin layer of nonconducting material called the _____. This layer can be air space, a vacuum, paper, ceramic, etc.
In a capacitor, the positive plate attracts the electrons of the dielectric, and the negative plate repels them. These forces cause the electrons to become _____.
______ is the ratio of the charge of either capacitor plate to the voltage difference between the plates. It's measured by the amount of electricity needed to raise the capacitors charge from zero to maximum.
A capacitor's charge is _____ (not moving).
The basic unit of capacitance is the _____.
A ___farad is equal to 0.000001 (1x10 ->-6) of a farad.
One ____farad is equal to 1x10->12 farads.
The four factors that influence capacitance are: ____ of the plates, ____ between the plates, if there's _____ material, and what the _____ is made of.
A material's _______ rates how well the material acts like a dielectric compared to a vacuum.
The term dielectric _____ refers to the maximum voltage can withstand without puncturing.
There will always be a small amount of current that escapes through a dielectric whenever voltage is applied across the capacitor's plates. This is called the _____ current.
Leakage current is measured in ______ or ______.
The two basic types of capacitor's are _____ and _____.
_____ capacitors have a fixed value. (value can't be changed)
_____ capacitors have adjustable plates. That is, the surface area of the plates can be varied.
One of the most common types of variable capacitors is the _____ capacitor.
Electrolytic capacitors can be classified as either ___ or ___.
A ___ electrolytic capacitor contains a positive plate suspended in a meta can filled with dielectric fluid. The can serves as the negative plate.
A ___ electrolytic capacitor is made of a rod of aluminum foil coated w/ aluminum oxide (an insulator) on 1 side. The alu. oxide acts as the dielectric and the foil is the positive plate. A layer of paraffined paper is put between the oxide foil & another foil layer. The 2nd layer is the negative plate. These are then wound up & 2 leads are attached. Everything is sealed in a metal can.
Electrolytic caps. are often called _____ capacitors because they only work properly when connected in a circuit in a specific way.
Three common types of electrolytic capacitors are _____ lead capacitors, _____ lead capacitors, and _______ capacitors.
The term _____ lead means that a lead is located at each end of the capacitor.
A _____ lead capacitor contains 2 leads that exit the bottom (only one side) of the capacitor.
________ electrolytic capacitors have solderless push-on "male" terminals, solder lugs, or screw-type terminals at the top of the capacitor.
____ capacitors are high-voltage capacitors that are commonly used in high-voltage transmitters and other types of oscillators that are used in the induction heating of metal products.
_____ capacitors consist of several layers of metal foil with deposits of ceramic material on them.
Ceramic capacitors are often called ____ capacitors due to their shape.
_____ capacitors are composed of two layers of foil separated by a paper dielectric.
In a _____ capacitor, tantalum pentoxide is used for the dielectric.
Tantalum capacitors are available in three forms: ____, ___ electrolytic, and ____ electrolyte.
A ____ tantalum capacitor is made of 2 layers of tant. foil. One of the layers is oxidized to produce a thin deposit of tant. pentoxide on its surface. The pentoxide acts as the dielectric. Everything is then rolled up and sealed in an aluminum case.
A ___ electrolyte tantalum capacitor is made form tant. powder pellets. The pellets are purified & welded into a porous mass. A layer of tant. pent. is formed on the surface of the pellets by passing current through them. Finally, everything is sealed in a tant. or silver can containing electrolyte solution.
A ____ electrolyte tantalum capacitor is constructed much like the wet elect. version. The tantalum pellets are coated w/ dry graphite, manganese dioxide, and silver powders. Everything is then sealed in a metal can or dipped in plastic resin.
The ________ capacitor is made of 2 layers of metal foil separated by a film of polyester. Another layer of polyester is then added to the outside of the capacitor to act as an insulator between the capacitor and the case.
A _____ capacitor contains a series of metal plates that mesh into or apart from one another when a knob at the front of the capacitor is turned. Because the plate area can change, the capacitance can vary.
The _____ capacitor is a type of variable capacitor. It contains a mica sheet between a stationary plate and an adjustable metal plate.
When capacitors are connected in parallel, the total capacitance of the circuit _____.
When capacitors are connected in series, the total capacitance of the circuit _____.
A *resistance-capacitance circuit* (called _______) is a circuit that contains both resistors and capacitors.
The time it takes for a capacitor to reach full charge depends on its ____ and the amount of _____ that's in series with it.
In an RC circuit, the length of time required for a capacitor to reach full charge is determined by the __________ of the circuit.
The time constant of a circuit is equal to the _____ times the _____ of the circuit.
A special meter called an *inductor/capacitor/resistor meter* (______) is used to directly measure a capacitors capacitance.
A _____ resistor is a very high-value resistor that's located across the terminals of a capacitor. It bleeds/removes the charge across the capacitor a few minutes after the circuit power has been removed.
