Here’s a glossary of low-voltage power terms and abbreviations, specifically for electronics, security, automation, access control, and other low-voltage systems. This is designed for engineers, installers, and tech-savvy consumers.
🔋 LOW-VOLTAGE POWER GLOSSARY
A
AC / Alternating Current – Electric current that periodically reverses direction; common in mains power.
Adapter / Power Adapter – Device converting mains AC to low-voltage DC for electronics.
Ampere / Amp (A) – Unit of electric current.
Amp-Hour / Ah – Battery capacity measure; how much current a battery can supply over one hour.
AV / Audio-Visual Power Supply – Low-voltage systems for home theatre and AV equipment.
B
Battery / Rechargeable Battery – Stores electrical energy for low-voltage systems.
Booster / Voltage Booster – Device increasing voltage for a circuit or device.
Bridging Power / Parallel Supply – Connecting multiple supplies to increase current capability.
Bus Bar / Power Distribution Bar – Metal bar distributing DC power to multiple devices.
Battery Management System (BMS) – Monitors and manages battery charging/discharging.
C
Cable / Conductor – Wire for transmitting low-voltage power.
Current / Amperage – Flow of electrical charge through a conductor.
Cutoff Voltage / Low-Voltage Disconnect (LVD) – Threshold where battery disconnects to prevent damage.
Circuit / Low-Voltage Circuit – Path for current flow in DC or AC low-voltage systems.
Charge Controller – Regulates battery charging from power sources (solar, DC supply).
D
DC / Direct Current – Electric current flowing in one direction; standard for low-voltage electronics.
Distribution / Power Distribution – Dividing supply to multiple devices safely.
Dropout Voltage – Minimum voltage difference needed for a regulator to maintain output.
Double Conversion / UPS Topology – Converts AC to DC and back to AC to stabilize output.
Device Rating / Max Current / Voltage – Maximum safe operating voltage or current for equipment.
E
Efficiency / Power Efficiency – Ratio of output power to input power in a supply.
Earth / Ground / Chassis Ground – Safety path for fault current; reduces risk of shock.
Electronic Fuse / Resettable Fuse – Protects circuits from overcurrent, automatically resets in some cases.
Enclosure / Power Box – Housing for low-voltage equipment and terminals.
End-of-Life / Battery Cycle Life – Battery lifespan measured in charge/discharge cycles.
F
Fuse / Overcurrent Protection – Safety device that interrupts flow if current exceeds rating.
Field Wiring / Installation Wiring – Wiring connecting devices in a low-voltage system.
Filter / EMI Filter – Reduces electrical noise and interference on low-voltage lines.
Form Factor / Power Supply Size – Physical size and mounting type of a supply unit.
Float Charging / Maintenance Charge – Low-rate charging to maintain battery at full capacity.
G
Ground Loop / Interference – Unwanted current path causing noise in electronics.
Gauge / Wire Gauge / AWG – Size of conductor affecting current-carrying capacity.
Grid / Power Grid Connection – Interface between mains and low-voltage systems.
GPS Power / Backup Supply – Dedicated low-voltage supply for GPS and security systems.
Galvanic Isolation / Transformer Isolation – Electrically isolates circuits to prevent interference or shock.
H
Heat Dissipation / Thermal Management – Removing excess heat from power supplies.
HVAC Low-Voltage Control – Using low-voltage DC or AC for building control systems.
High Current / Low Voltage – Systems supplying large currents at low voltage.
Horsepower Equivalent / Power Rating – Conversion of electrical power to mechanical output.
Hybrid Power Supply / Multi-Input – Supply accepting AC and DC inputs.
I
Input Voltage / Voltage Range – Acceptable voltage supplied to a power supply.
Isolated Supply / Isolation Transformer – Provides electrical separation for safety and noise reduction.
Inrush Current / Surge Current – Brief high current when powering on devices.
Indicator / LED / Status Light – Shows operational status of low-voltage supply.
Internal Resistance / Battery IR – Resistance inside battery affecting voltage under load.
J
Junction Box / Terminal Box – Enclosure where multiple cables are joined.
Joule / Energy Unit – Electrical energy delivered or stored (1 J = 1 W·s).
Jump Wire / Bridging Wire – Short wire connecting terminals or circuits.
Jack / DC Connector – Standard plug for connecting low-voltage devices.
Jobsite Wiring / Installation Wiring – Wires installed for low-voltage devices on site.
K
Kelvin / Temperature Rating – Maximum ambient temperature for safe operation.
Keying / Polarization – Prevents reverse connection of DC power plugs.
Kilowatt / kW / Power Rating – Large-scale measure of electrical power.
Knockout / Enclosure Opening – Pre-cut opening in box for cable entry.
L
Load / Device Load – Power drawn by connected devices.
LED Driver / Low-Voltage Lighting – Supplies regulated current to LEDs.
Line Voltage vs Low Voltage – Mains AC (120–240V) vs low-voltage DC (5–48V).
Low-Voltage Disconnect / LVD – Protects battery from deep discharge.
Lithium-Ion / Li-Ion Battery – Rechargeable battery type common in security and consumer electronics.
M
Maximum Current / Overload Rating – Peak current supply before protection trips.
Mounting / DIN Rail / Wall Mount – Installation method for power supplies.
Metering / Current & Voltage Monitoring – Displays real-time electrical parameters.
Microcontroller Power / Logic Voltage – 3.3V or 5V DC supply for electronics.
Multi-Output Supply / Multi-Rail – Supply providing several voltages simultaneously.
N
Nominal Voltage – Standard voltage rating for devices or batteries.
Noise / Ripple Voltage – Small unwanted fluctuations in DC output.
Non-Isolated Supply – Shares ground with input; may be cheaper but less safe.
NiMH / Nickel-Metal Hydride Battery – Rechargeable battery type for low-voltage devices.
Networked Power Supply / PoE – Power supplied via data network (Power over Ethernet).
O
Overcurrent / Overload Protection – Prevents damage from excessive current.
Overvoltage Protection / Surge Protection – Prevents voltage spikes from damaging equipment.
Output Voltage / Regulated Voltage – Voltage delivered to device.
Open Circuit / No Load Voltage – Voltage when supply is not connected to a load.
Outdoor-Rated Supply / IP Rating – Weatherproof enclosure for external use.
P
Power Supply / PSU – Converts mains AC to low-voltage DC or regulated AC.
PoE / Power over Ethernet – Network cable providing data and low-voltage DC power.
Peak Current / Surge Capacity – Short-duration maximum current a supply can handle.
Parallel Wiring / Current Sharing – Connecting supplies to increase total current capacity.
Polarity / Positive-Negative Orientation – Correct wiring direction for DC devices.
Q
Quick Connect / Plug Terminals – Fast wiring connection for low-voltage devices.
Quiescent Current / Standby Current – Current drawn when device is idle.
Quality / Efficiency Rating – Power efficiency, heat generation, and reliability metric.
R
Regulated Supply / Constant Voltage – Voltage stays stable despite load changes.
Ripple / Voltage Ripple – AC fluctuations superimposed on DC output.
Rectifier / AC-DC Conversion – Converts AC mains to DC voltage.
Redundancy / Backup Power – Extra supply for continuous operation.
Remote Sensing / Voltage Compensation – Adjusts output at load to overcome voltage drop in cables.
S
Short Circuit / Protection – Safety feature stopping current flow during a fault.
Step-Down / Buck Converter – Reduces voltage from higher to lower DC.
Step-Up / Boost Converter – Increases voltage from lower to higher DC.
Solar Charging / Photovoltaic Input – Charging batteries from solar panels.
Standby Power / Idle Consumption – Power used when device is on but inactive.
T
Transformer / Isolation Transformer – Changes AC voltage level or provides isolation.
Terminal Block / Screw Terminal – Connection point for wiring devices.
Threshold Voltage / Cutoff – Voltage at which protection activates.
Trickle Charge / Maintenance Charging – Small current to maintain battery at full charge.
Temperature Coefficient / Thermal Protection – Limits overheating of supply or battery.
U
UPS / Uninterruptible Power Supply – Provides backup low-voltage DC or AC during mains failure.
Under-Voltage / Low Voltage Lockout – Prevents battery damage from deep discharge.
USB Power / Charging Voltage – 5V or higher for low-power electronics.
Universal Input / Wide Input Range – AC input from 100–240V for global use.
Utility Power / Grid Supply – Standard mains AC providing input for low-voltage conversion.
V
Voltage / V – Electrical potential difference.
Voltage Drop / Cable Drop – Loss due to resistance of cables over distance.
Voltage Regulator / VR – Device keeping output voltage constant.
Virtual Ground / Split Supply – Simulated zero-voltage reference in electronics.
Vented Enclosure / Cooling – Allows heat dissipation in enclosed low-voltage devices.
W
Watt / Power Rating – Electrical power delivered (Voltage × Current).
Wire Gauge / AWG / Conductor Size – Determines maximum safe current.
Weatherproof / Outdoor Rating – IP-rated low-voltage devices.
Wiring Diagram / Schematic – Shows connections and power flow.
Wall-Mounted PSU / DIN Rail PSU – Standard installation methods for low-voltage supplies.
X
XLR Power / Balanced DC – Connector type sometimes used in professional audio or lighting.
X-cap / Filter Capacitor – Component reducing noise in power circuits.
Y
Yield / Efficiency – Ratio of output power to input power.
Y-Cable / Split Power / Parallel Output – Distributes power to multiple devices.
Yellow / Positive Wire Convention – Color coding for low-voltage DC positive.
Z
Zero Load / No Load Power – Power consumption when supply has no connected device.
Zener Diode / Voltage Clamp – Protects devices from voltage spikes.
Zone Power Distribution – Dividing low-voltage supply into different functional zones.
Published 17th Feb 2026