Electrical reactance
Resonance
Filters
Voltage Divider
Capacitor Charge
Operational Amplifier
Circuit with IC 555
Electric Power Calculations
Wye-Delta Transformation
Frequency
Logic Gates
FET
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Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current which flows only in one direction. The usual waveform of alternating current in most electric power circuits is a sine wave, for being the more efficient form of electric energy transmission. In certain applications, different waveforms are used, such as triangular or square waves. While the DC source is constituted by positive and negative poles, the AC is constituted by phases (and, many times, by the neutral conductor).
AC Generators
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Commutator Ring
DC Generators
An inductor usually consists of a coil of conducting material, typically insulated copper wire, wrapped around a core either of plastic or of a ferromagnetic material; the latter is called an "iron core" inductor. When the current flowing through an inductor changes, the time-varying magnetic field induces an electromotive force. Small value inductors can also be built on integrated circuits using the same processes that are used to make transistors. Aluminum interconnect is typically used, laid out in a spiral coil pattern. However, the small dimensions limit the inductance, and it is far more common to use a circuit called a gyrator that uses a capacitor and active components to behave similarly to an inductor.
Inductors used to block very high frequencies are sometimes made by stringing a ferrite bead on a wire.
Resistor Measurement