Electrical4U What is an Essential Node? A node is a connected set of ideal conductors whose element terminals share one voltage. An essential node has three or more connected circuit elements. The first circuit has seven nodes. Four are essential and marked green; the other three join only two elements and are marked red. What is … Read more
What is Available Fault Current? Available fault current (AFC), also called available short-circuit current, is the maximum prospective current at a specified point for a stated fault and set of system conditions. Its value changes with source and circuit impedance. NFPA 70 added Section 110.24 in the 2011 National Electrical Code (NEC). The 2026 edition … Read more
Formulas For Electrical Engineering Electrical engineering applies electricity, electronics and electromagnetism to circuits, machines, power systems, communications and control. Topics include power systems, electrical machines, power electronics, computing, signal processing, telecommunications and control system design. Formulas relate measured quantities, but each equation is valid only under its stated circuit and modelling assumptions. The sections below … Read more
What is a Pull-up Resistor? A pull-up resistor connects an undriven signal node towards the positive supply and gives it a defined high level. Designers use pull-ups with transistors and switches. A pull-down gives the opposite default by connecting the node towards ground instead of Vcc through a pull-down resistor. The component is a standard … Read more
What is a Pull-Down Resistor? A pull-down resistor connects an undriven signal node to ground and gives it a defined low level. Designers often use one with transistors or switches. A pull-up performs the opposite function by connecting the node towards Vcc through a pull-up resistor. A switch connected from the input to the positive … Read more
What is a Grounding Conductor? A grounding conductor is a wire or bar earthed on purpose, called the equipment grounding conductor (EGC) in US practice, and also a ground wire or case ground. The EGC is bonded to the metal case of a box, appliance or tool, also called a case ground. The grounding conductor … Read more
What is a Permanent Split Capacitor Motor? A permanent split capacitor motor, or PSC motor, is a single-phase induction motor whose run capacitor remains connected in series with the auxiliary winding during starting and running. This single-phase induction motor has a stator with main and auxiliary windings plus a squirrel-cage rotor. Unlike a capacitor-start motor, … Read more
What is DSP? Digital Signal Processing (DSP) uses numerical algorithms to analyse, transform or generate sampled signals. Communications is one application, alongside audio, imaging, sensing and control. A data-acquisition system samples and quantises physical signals such as audio, video, pressure, temperature and position with an analog-to-digital converter (ADC). Sensor conditioning and anti-alias filtering may be … Read more
What is a Fast Recovery Diode? A fast recovery diode (also called a fast diode or fast switching diode) is a PN-junction rectifier designed to stop conducting soon after its voltage reverses. Its short reverse recovery limits stored charge and switching loss, which makes the device useful in high-frequency rectifiers, converters and freewheeling circuits. A … Read more
What is an Inductor? Series and parallel inductor networks combine two or more coils to obtain an equivalent inductance. Each inductor is a two-terminal passive electrical element that stores energy in the form of a magnetic field when electric current flows. Depending on its use, it may be called a coil, choke or reactor. For … Read more