Information Systems Support and Integration cheat sheet

Key terms

Resistor

Limits and controls the flow of current in a circuit; its value is measured in ohms (Ω).

Capacitor

Stores and releases electrical charge, used for filtering and smoothing power in a circuit.

Diode

Allows current to flow in one direction only, used for rectification (converting AC to DC).

Transistor

A semiconductor device that amplifies or switches electronic signals; millions of microscopic transistors etched onto silicon are what a modern CPU actually is.

Integrated circuit (IC)

A complete circuit, resistors, transistors and all, fabricated on a single small chip of semiconductor material, e.g. the CPU, RAM chips, and a motherboard's chipset.

Printed Circuit Board (PCB)

The rigid board (e.g. a motherboard) that physically holds components and connects them electrically through etched copper traces.

Direct Current (DC)

Current that flows in one constant direction; what every internal computer component (CPU, RAM, drives) actually runs on.

Alternating Current (AC)

Current that periodically reverses direction; what the wall socket supplies, converted to DC by the Power Supply Unit (PSU) before it reaches any internal component.

Semiconductor

A material (typically silicon) whose conductivity sits between a conductor and an insulator, and can be precisely controlled; the physical basis of diodes, transistors and every IC described under electronic components.

Screwdriver set

Phillips and flat-head, in the small sizes computer cases and expansion cards use; the single most-used tool for any hardware job.

Anti-static wrist strap

Clipped to an earthed point and worn on the wrist, it continuously discharges static electricity from the technician's body before it can damage a sensitive component (see Safety precautions, below).

Multimeter

Measures voltage, current and resistance; used to test whether a PSU, cable or component is delivering the power it should.

Compressed air / anti-static brush

Clears dust from fans, heatsinks and vents without touching (and risking scratching or discharging static onto) sensitive components.

Thermal paste

Fills microscopic gaps between a CPU and its heatsink so heat transfers efficiently; reapplied whenever a heatsink is removed.

Cable ties / management tools

Keep internal cabling tidy, improving airflow and making the next repair easier to work in.

Preventive maintenance

Scheduled, routine work done before a fault occurs, dust removal, thermal paste renewal, cable inspection, software updates, to reduce the chance of failure.

Corrective maintenance

Work done in response to an actual fault, diagnosing and repairing or replacing whatever failed.

Documentation

Recording what was done, when, and by whom, on every maintenance visit; essential both for warranty/audit purposes and so the next technician does not repeat wasted diagnostic steps.

Electrostatic discharge (ESD)

A sudden, invisible static-electricity discharge that can permanently damage a component; prevented with the wrist strap, an anti-static mat, and touching a grounded metal surface before handling any component.

Power safety

Always power off and unplug a system, and discharge the PSU's residual capacitors, before opening the case; never work on live power.

Environmental safety

Keep liquids away from equipment, work in a dry, well-ventilated area, and never obstruct a system's ventilation once reassembled, overheating is itself a safety risk, not just a performance one (see the troubleshooting chapter).

Manual handling

Lift heavy equipment (towers, printers, monitors) with correct posture, and use two people or a trolley for anything awkward or heavy.

Fire safety

Never use water on an electrical fire; a CO₂ or dry-powder extinguisher rated for electrical equipment is the correct response.