DC Electronic Circuits — Maintenance and Safety (Strand 10)

hazard + exposure = risk

Formula for assessing risk in electrical circuits.

electric shock

Primarily about current through the body, not just AC or DC.

effective resistance

Resistance in the contact path that determines current through the body.

Ohm's Law

Relationship defined by the equation $I = \frac{V}{R}$.

risk assessment

Evaluating maximum voltages, available current, and energy storage.

thermal hazards

Injury risks from heat generated by electrical components.

capacitors

Devices that store charge/energy and can hold voltage after power is removed.

discharge resistor

Component used to safely discharge capacitors.

one-hand technique

Safe probing practice to minimize current path through the body.

foreign object control

Keeping workspaces clear of conductive debris during maintenance.

current-limited power supply

Tool for safely powering circuits to prevent damage during testing.

ESD (Electrostatic Discharge)

Sudden transfer of static electricity causing potential damage to components.

triboelectric charging

Static charge buildup from contact and separation of materials.

high input impedance

Characteristic of sensitive devices vulnerable to ESD.

ESD-safe environment

Controlled workspace designed to limit static electricity risks.

conductive materials

Allow free movement of charge, providing risk of short-circuiting.

insulative materials

Prevent charge movement and can hold static charge.

DMM (Digital Multimeter)

Tool used for voltage, current, and resistance measurements.

continuity test

DMM test to determine if there is a complete electrical path.

safe soldering practices

Involves ventilation and proper handling of soldering equipment.

solder joint integrity

Assessment of the quality and reliability of solder connections.

preventive maintenance

Regular servicing aimed at preventing equipment failure.

visual inspection

Technique used to identify faults by examining components.

thermal management

Actions taken to maintain optimal operating temperatures of components.

grounding confusion

Misunderstanding ground references in circuits leading to errors.

fuses

Devices that protect circuits by breaking connection under excessive current.

resettable fuses

PTC devices that limit current and reset when cooled.

reverse polarity protection

Circuits designed to prevent damage from reversed connection of power.

flyback diode

Protective device used with inductive loads to prevent voltage spikes.

documentation in maintenance

Records that help trace repairs, faults, and expected conditions.

housekeeping practices

Organizational habits to maintain a safe and efficient work environment.

environmental responsibility

Optional adherence to regulations for safe disposal of waste materials.

soldering iron safe use

Preventing burns and accidents by practicing proper handling.

ESD safe packaging

Special packaging to protect components from electrostatic damage.

maintenance logs

Records documenting maintenance performed and observations made.

measuring DC voltage safely

Allows workers to avoid short-circuiting or damaging meters.

chemical exposure hazards

Risks associated with battery leaks and electrolyte contact.

high fault current

Significant current flow potential during short circuits in batteries.

thermal runaway

Condition where battery overheating leads to failure and fire.

current measurement series connection

Method requires a circuit to be open to insert the meter.

power supply safety measures

Set voltage and current limits before energizing circuits.

intermittent faults

Flaky issues that appear and disappear, often due to connections.

calibration checks

Verifying equipment outputs to maintain measurement accuracy.

component aging risks

Failure due to prolonged exposure to unfavorable conditions.

circuit isolation

Preventing accidental energization during maintenance.

solder wick

Used to absorb molten solder for desoldering components.

personal protective equipment (PPE)

Gear worn to minimize exposure to hazards during maintenance.

damp working surfaces

Increase risk of electric shock due to reduced contact resistance.

supply voltage monitoring

Checking voltage reliability under load conditions.

circuit shorts

Common failure resulting from unintended conductive paths occurring.

component sourcing knowledge

Understanding required parts for accurate repairs.

environmental control for ESD

Managing humidity levels to limit static charge buildup.