Electrical & Electronic Systems

Current Divider

A circuit that splits a current into two or more branches.

Batteries

Devices that store and supply electrical energy through chemical reactions.

Charge Capacity

The total amount of electric charge a battery can store, usually measured in ampere-hours (A·h).

Internal Resistance

Resistive losses within a battery that cause the terminal voltage to drop under load.

Efficiency (η)

The ratio of useful power output to total power input, often expressed as a percentage.

Ampere-Hour (A·h)

A unit of electric charge equal to one ampere flowing for one hour.

Nominal Voltage (Vs)

The stated voltage of a battery, typically under no load conditions.

Terminal Voltage (Vt)

The voltage output of a battery while under load, accounting for internal resistance.

Voltage Divider Equation

A formula used to calculate the terminal voltage across a load resistor in the presence of internal resistance.

Power Transfer Efficiency

The effective transfer of power from a source to a load.

Energy Stored in a Battery

Calculated as stored charge multiplied by voltage: W = Q × V.

Voltage Source

An ideal device that maintains a constant voltage regardless of the current drawn.

Chemical Potential Energy

The energy stored in a battery due to its chemical composition.

1 A·h to Coulombs (C)

1 A·h is equal to 3600 C.

Lead-Acid Battery

A type of rechargeable battery known for its high charge capacity and low internal resistance.

Coin Cell Battery

A small, round battery commonly used in watches and small electronic devices.

Simulation

An experiment or model that replicates the behavior of real-world systems to analyze performance.

Power Dissipation

The process of energy being converted into heat within components like resistors.

KVL (Kirchhoff's Voltage Law)

A law stating that the total voltage around a closed loop in a circuit must be zero.

Ohm's Law

A fundamental law stating that V = I × R, where V is voltage, I is current, and R is resistance.

coulomb (C)

The unit of electric charge, defined as the charge transported by a constant current of one ampere in one second.

Ideal Voltage Source

A voltage source that provides a constant voltage, regardless of the current drawn from it.

Load Resistor (Rl)

A resistor connected to a power source in a circuit that consumes power.

Energy Density of TNT

Approximately 4.18 MJ/kg, used as a comparison for energy stored in batteries.

Inductive Load

A load in which the current lags behind the voltage due to inductance.

RLC Circuit

A circuit containing resistors (R), inductors (L), and capacitors (C) which can affect the phase and amplitude of voltages and currents.

Transient Response

The behavior of a circuit immediately after a change in voltage or current before it reaches a steady state.

Steady State Response

The behavior of a circuit after transients have settled; consisting of constant voltages and currents.

Phasor Representation

A complex number representation of sinusoidal functions used in AC circuit analysis.

Impedance (Z)

The total opposition a circuit presents to AC current, combining resistance and reactance.

Reactance

The resistance of a capacitor or inductor to a change in current; frequency-dependent.

Capacitance (C)

A measure of a capacitor's ability to store charge, expressed in farads (F).

Inductance (L)

A measure of an inductor's ability to store energy in a magnetic field, expressed in henries (H).

RMS Voltage (Vrms)

The effective value of an AC voltage, calculated as Vpeak/√2.

Average Power (Pavg)

The average amount of power dissipated over one complete cycle of an AC waveform.

Inductor Impedance

The impedance of an inductor, represented as ZL = ωL∠π/2, where ω is the angular frequency.

Phase Difference

The difference in phase between the voltage and current in AC circuits.

Admittance

The inverse of impedance, represented as Y = 1/Z, measured in siemens (S).

Voltage Divider Rule

A rule that relates the voltages across components in a series circuit: V2 = Z2/(Z1 + Z2) * Vtotal.

Impedance (Z)

The measure of opposition that a circuit presents to a current when a voltage is applied, defined as Z = R + jX.

Reactance (X)

The imaginary part of impedance, which can be positive (capacitive) or negative (inductive).

Phasor

A complex number representing the magnitude and phase of sinusoidal functions used in AC circuit analysis.

Phasor Analysis

A method to analyze AC circuits using phasors to represent voltages and currents.

Complex Power (S)

The power term S = P + jQ where P is real power and Q is reactive power.

Power Factor

The cosine of the phase angle, representing the efficiency of power usage in a circuit.

Transfer Function (vout/vin)

A function that expresses the relationship between the output voltage and the input voltage, often dependent on frequency.

Synchronous Speed

The speed at which the magnetic field in a motor rotates, determined by the supply frequency and number of poles.

Inductive Load

A type of load where the current lags the voltage by 90°, resulting in reactive power flow.

Capacitive Load

A type of load where the current leads the voltage by 90°, resulting in reactive power flow.

DC Generator Action

When a mechanical energy is converted into electrical energy using a commutator to produce DC voltage.

Power Factor Correction

The process of adjusting a load to reduce the amount of reactive power consumed and improve energy efficiency.

Eddy Currents

Currents induced in the core of transformers that lead to energy losses due to resistive heating.

Hysteresis Loss

Energy loss in transformer cores due to the repeated magnetization and demagnetization of core material.

Electrical Machine

A device that converts electrical energy into mechanical energy (motor) or mechanical energy into electrical energy (generator).

Reactance (X)

The opposition to the change in current flow in an AC circuit, can be capacitive or inductive.

Turbine

A device that converts kinetic energy from fluids (water, steam, air) into mechanical energy for generating electricity.

Transformer

A device that transfers electrical energy between two or more circuits through electromagnetic induction.

Primary Winding

The coil of a transformer that receives energy from the source.

Secondary Winding

The coil of a transformer that delivers energy to the load.

Synchronous Machine

An AC machine in which the speed of the rotor and the rotating stator magnetic field are synchronized.

Induction Motor

An AC motor that operates with a rotor that is always slower than the synchronous speed.

Reactive Power (Q)

The power that oscillates between the source and the reactive components (inductors or capacitors) in the circuit.

Appliance Motor

An electric motor used in household appliances that converts electrical energy into mechanical energy.

AC Supply

Alternating current supply where the voltage alternates in polarity, typically at frequencies of 50 Hz or 60 Hz.

Load Impedance

The total opposition that a load presents to the flow of electric current, consisting of resistance and reactance.

Electrical Substation

Physical location where electrical energy is transformed, controlled and monitored as it flows between various networks.

Energy Storage

Systems designed to store electrical energy for later use, helping to balance supply-demand fluctuations.

Solar PV System

A system that converts sunlight into electricity using photovoltaic cells.

Hydropower

The generation of electricity by harnessing the energy of flowing or falling water.

Wind Turbine

A device that converts kinetic energy from wind into mechanical energy, which is then converted to electricity.

Battery Energy Storage System

A system that stores electrical energy in batteries for later use, enhancing stability and reliability of power supply.

DC Machine

An electrical machine that converts direct current electrical energy into mechanical energy (motor) or mechanical energy into electrical energy (generator).

Back EMF (E)

The induced voltage that opposes the change in current in a motor, calculated as E = k.ω.

Torque (τ)

The rotational force produced by a motor, given by τ = k.i, where i is the current in the windings.

Ideal DC Machine Model

Assumes that back EMF (E) equals the terminal voltage (v) and indicates 100% efficiency.

Stall Current (istall)

The current through the motor when the speed is zero, calculated as istall = v/Rw.

No-load Speed (ωnoload)

The speed of the motor when there is no load, corresponding to zero output torque.

Efficiency (η)

The ratio of output power to input power in a machine that can be calculated for both motor and generator operation.

Equivalent Circuit Model

A simplified circuit representation of a DC machine that includes terminal voltage, current, and winding resistance.

Mechanical Power Output (PM)

The power produced by the motor calculated as PM = τ.ω.

Electrical Power Input (PE)

The electrical power supplied to the motor, equal to PE = v.i.

Torque-Speed Characteristic

A graphical representation that shows how torque varies with motor speed in DC machines.

Load Line

The characteristic of the load that the machine is driving, indicating how the machine's speed and torque behave under load.

Zener Diode

A type of diode that allows current to flow in the reverse direction when a specific reverse voltage (Zener voltage) is reached.

Clippers

Circuits that remove portions of an input signal, typically implemented with diodes, to protect circuits from voltage spikes.

Clamp Circuits

Circuits that add a DC offset to AC waveforms, altering their peaks to specific levels.

Light Emitting Diode (LED)

A diode that emits light when current flows through it in the forward direction.

Integration Amplifier

An operational amplifier circuit that produces an output voltage proportional to the integral of the input voltage.

Differentiating Amplifier

An operational amplifier circuit that outputs a voltage proportional to the rate of change of the input voltage.

Voltage Amplifier

An amplifier that produces an output voltage proportional to its input voltage, described by the equation vout(t) = A.vin(t).

Operational Amplifier (Op-Amp)

A high-gain voltage amplifier with a differential input, widely used in analog electronics.

Inverting Amplifier

An op-amp configuration where the output is inverted and proportional to the input, with a gain determined by feedback resistors.

Non-inverting Amplifier

An op-amp configuration that amplifies the input voltage without inverting it, again with gain determined by resistor values.

Bipolar Junction Transistor (BJT)

A type of transistor formed by three layers of semiconductor material that functions as a current-controlled device.

MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor)

A type of transistor that is voltage-controlled and used for switching and amplifying electronic signals.

Transistor as a Switch

Using a transistor to control the flow of current in a circuit, effectively functioning as an electronic switch.

Pinch-off

The phenomenon in MOSFETs where the conducting channel narrows and current stabilizes after a certain threshold voltage.

Gain (A)

The ratio of output voltage to input voltage in an amplifier, representing how much the input is amplified.

Electrical Equivalent of a Motor

The model that involves viewing a motor in terms of electrical parameters to analyze its behavior mathematically.

Flyback Diode

A diode used to protect a circuit by providing a path for voltage spikes generated when a coil is de-energized.