Maharashtra HSC Electronics Field Technician (NSQF F6) key terms

The relationship stating that current through a conductor equals the voltage across it divided by its resistance, written as I = V/R. It underpins nearly every circuit calculation a technician performs.

The property of a material that opposes the flow of electric current, measured in ohms. It converts electrical energy into heat and depends on material, length, cross-section and temperature.

A standard banding scheme on resistors in which each colour represents a digit or multiplier, with the last band showing tolerance. It lets a technician read value without a meter.

The permitted deviation of a component's actual value from its marked value, usually expressed as a percentage. A 100 ohm resistor with 5 percent tolerance may read anywhere from 95 to 105 ohms.

The ability of a component to store electric charge per unit of applied voltage, measured in farads. Capacitors block steady direct current while passing changing signals, which makes them useful for coupling and filtering.

Families of charge-storing components such as ceramic, electrolytic, film and tantalum. Each differs in polarity, stability, leakage and typical use, so substitution requires matching the original's characteristics.

The orientation of positive and negative terminals in a component or supply. Reversing it on an electrolytic capacitor or a DC supply can destroy the part or damage the equipment it feeds.

A two-terminal semiconductor that conducts readily in one direction and blocks the other. It is used for rectification, reverse-polarity protection and flyback suppression across inductive loads.

A diode designed to operate safely in reverse breakdown at a specified voltage. In that region it holds a nearly constant voltage, so it serves as a simple shunt regulator or reference.

A three-terminal semiconductor in which a small base current controls a larger collector current. It works as a switch or amplifier, and its two types differ in current direction and supply polarity.

A transistor in which voltage on an insulated gate controls current through a channel, drawing almost no gate current. It is common in power switching and logic-level drive circuits.

Two basic ways of connecting components. In series the same current flows through each part and voltages add; in parallel the same voltage appears across each part and currents add.

Two rules for analysing networks: current entering a junction equals current leaving it, and the algebraic sum of voltages around any closed loop is zero. They extend Ohm's law to complex circuits.

The rate at which a component converts electrical energy into heat, equal to voltage times current or current squared times resistance. Exceeding a part's rating causes overheating and early failure.

A pair of magnetically coupled windings that changes alternating voltage levels without changing frequency. The turns ratio sets the step-up or step-down factor, and it provides isolation between circuits.

A general-purpose instrument combining voltmeter, ammeter and ohmmeter functions, often with continuity and diode test. Correct range and terminal selection is essential to avoid damage or wrong readings.

An instrument that plots signal voltage against time on a phosphor screen, showing waveform shape, amplitude, frequency and phase. It is the primary tool for tracing distortion and timing faults.

The horizontal sweep setting of an oscilloscope that determines how much time each division represents. Adjusting it lets a technician measure period, pulse width and rise time accurately.

The fixed division ratio, commonly ten to one, by which a scope probe reduces the signal before it reaches the instrument. Forgetting to match the scope setting to the probe gives readings ten times too low.

The error caused when an instrument's own impedance draws current from the circuit under test and alters the very quantity being measured. High-impedance meters minimise this disturbance.

A meter whose jaws sense the magnetic field around a conductor to read current without breaking the circuit. It suits mains and motor cables where series insertion is impractical or unsafe.

A instrument applying a high DC test voltage, often 500 volts, to measure leakage through insulation in megohms. Low readings reveal moisture, cracks or contamination before they cause shock or fire.

Checking parts in or out of circuit using resistance, diode and continuity modes to confirm expected behaviour. Comparing against a known-good part is often more reliable than absolute readings.

A stage that converts alternating current to direct current using diodes, then smooths the pulses with capacitors and sometimes inductors. Ripple remaining on the output indicates worn filter capacitors or overload.

Four diodes arranged so both half-cycles of an AC input are converted to the same output polarity. It gives full-wave rectification without a centre-tapped transformer.

A network of capacitors, inductors and resistors that passes wanted frequencies while attenuating others. It reduces ripple in power supplies and separates bands in signal paths.

A circuit that holds its output voltage steady despite changes in input voltage or load current. Linear types dissipate excess as heat; switching types chop the input for higher efficiency.

A circuit that increases the amplitude of a signal using an external power source. Its key ratings are gain, bandwidth, input impedance and distortion, and each stage is coupled to the next.

Setting the steady operating point of an active device so it stays in the desired region for the whole signal swing. Incorrect bias causes clipping, crossover distortion or overheating.

A basic digital building block that produces an output determined by fixed rules on its inputs, such as AND, OR, NOT, NAND and NOR. Truth tables describe each gate's behaviour completely.

A set of rules for manipulating binary variables using AND, OR and NOT operations. Simplifying expressions with it reduces the number of gates needed in a circuit.

A bistable digital element that stores one bit and changes state only on a clock edge or control input. It forms the basis of counters, registers and memory.

A single chip containing a processor, memory and programmable input-output peripherals. It runs firmware to read sensors, make decisions and drive outputs in appliances and automation systems.

A general-purpose input-output pin on a microcontroller whose direction and logic level are set by software. It connects the controller to switches, LEDs, relays and other devices.

A peripheral that converts a continuous voltage into a discrete number proportional to it, set by resolution and reference voltage. It lets a microcontroller read sensors such as thermistors and potentiometers.

Rapid switching of a digital output where the proportion of on-time controls average power delivered. It dims lamps, varies motor speed and drives switching regulators efficiently.

A device that converts a physical quantity such as temperature, light, pressure or motion into an electrical signal. Correct placement, supply and calibration determine whether readings are trustworthy.

An interface stage, often a transistor with a flyback diode, that lets a low-power control signal switch a relay coil. It protects the controller from inductive kickback and excess current.

Connecting exposed metalwork and the supply neutral point to the ground so fault current trips protection and touch voltage stays safe. Poor earthing is a leading cause of electric shock.

A protective switch that trips when the current in live and neutral conductors differs by a small set amount, indicating leakage to earth. It guards people against shock, not against overload.

Wearable safety gear such as insulated gloves, goggles, footwear and helmets selected for the task's hazards. It supplements safe procedures and never replaces isolation of the supply.