Glossary of Key Terms
Glossary of Key Terms
| Term | Definition |
| AC Voltage Controller | A device used to vary the value of alternating voltage applied to a load circuit, typically by using a thyristor to control the triggering angle. |
| Base Transport Factor (αT) | A parameter in a BJT, given by the ratio of (IE,n – Ir,b) / IE,n, where IE,n is the electron diffusion current and Ir,b is the base recombination current. |
| Bipolar Junction Transistor (BJT) | A transistor whose operation depends on the contact made by two semiconductors and requires two types of charge carriers (holes and electrons). It can act as a switch, amplifier, or oscillator. |
| Capacitor | An electrical device with two conducting plates separated by a dielectric insulator that stores electric energy in an electric field. |
| Chopper | A device that uses high-speed switching to connect and disconnect from a source load, converting a fixed DC voltage to a variable DC voltage. |
| Current Gain (β) | In a BJT, the ratio of the collector current (IC) to the base current (IB). It is a measure of the transistor’s ability to produce current amplification. |
| Cycloconverter | A frequency changer that converts AC power from one frequency to AC power at another frequency in a single stage. |
| Dual Converter | A power electronic circuit consisting of two converters linked back-to-back, mainly found in variable speed drives (VFDs). |
| Duty Ratio (D) | In a chopper, the ratio of the ON time to the total chopping time period (TON/T). It is used to control the output voltage. |
| Emitter Efficiency (γE) | A parameter in a BJT given by the ratio of the electron diffusion current to the sum of the electron and hole diffusion currents. |
| Form Factor (FF) | A performance parameter for converters, defined as the ratio of the RMS voltage on the load (VL) to the DC voltage on the load (VDC). |
| Inductor | An electronic device that uses a magnetic field to store electric energy, typically in the form of a coil or wire loop. |
| Insulated Gate Bipolar Transistor (IGBT) | A three-terminal semiconductor device used as an electronic switch, combining the characteristics of MOSFETs (isolated gate) and BJTs (high current, low saturation voltage). |
| Integral Cycle Control | A method of direct AC-to-AC conversion that operates by combining and eliminating higher frequency half cycles from an AC input, achieving switching at zero voltage. |
| Inverter | A power electronic device that converts power in DC form to AC form at a required frequency and output voltage. |
| Linear Circuit Elements | Components in an electrical circuit that exhibit a linear relationship between the current input and the voltage output, such as resistors, capacitors, and inductors. |
| Matrix Converter | A converter with a single stage of conversion that uses bidirectional controlled switches to automatically convert power from AC to AC. |
| Metal Oxide Semiconductor Field Effect Transistor (MOSFET) | A type of transistor used to switch electronic signals, featuring an isolated gate that gives it extremely high input resistance. |
| Phase Controlled Converter | A converter that changes fixed-frequency, fixed-voltage AC power into a variable DC voltage output by altering the phase angle at which thyristors are triggered. |
| Power Electronics | The process of controlling the flow of current and voltage and converting it to a form suitable for user loads. |
| Pulse Width Modulation (PWM) | A technique used to reduce the total harmonic distortion (THD) in a load current by modulating the pulse width of a rectangular wave to create a variable average waveform value. |
| Resistor | A device in which the flow of an electric current is restricted, resulting in a conversion of energy (e.g., to heat or light). |
| Resonant Switch Converter | A converter that contains an inductor-capacitor (L-C) network, causing current and voltage waveforms to vary sinusoidally during each switching period. |
| Ripple Factor (RF) | A performance parameter for converters that measures the ripple content in the output, calculated as sqrt(FF² – 1). |
| Silicon Controlled Rectifier (SCR) | A four-layer solid-state current-controlling device (a type of thyristor) used in applications requiring control of high voltage and power. |
| Switched Mode Power Supply (SMPS) | An electronic device that uses a switching regulator to convert electrical power efficiently by switching ON and OFF during low dissipation periods. |
| Transformer | A device that alters energy from one level to another through electromagnetic induction, typically used to raise or lower AC voltages. |
| Transformer Utilization Factor (TUF) | A performance parameter for converters, defined as the ratio of the DC power output to the VA rating of the transformer. |
| Transport Factor (α) | In a BJT, the ratio of the collector current to the emitter current. |
| TRIAC (Triode for Alternating Current) | A three-terminal, bi-directional semiconductor device that can control the flow of current in both halves of an AC cycle. |