Glossary of Technical Terms – Hygrometers, Timers, and Clocks Explained

A comprehensive reference for technical terms used in environmental monitoring and timekeeping

2026-09-27 19:51 kai

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This glossary defines key technical terms related to hygrometers, timers, and clocks. Use it as a reference when reviewing product specifications, calibration documents, or technical discussions.

Hygrometer and Thermometer Terms

Term	Definition
Accuracy	How close a measurement is to the true value. Expressed as ± value (e.g., ±0.5°C).
Calibration	The process of comparing an instrument's readings against a reference standard and adjusting if necessary.
Capacitive Sensor	A humidity sensor that measures changes in capacitance caused by moisture absorption.
Chilled-Mirror Hygrometer	A highly accurate hygrometer that measures humidity by cooling a mirror until condensation forms.
Dew Point	The temperature at which air becomes saturated with moisture and condensation begins.
Drift	The gradual change in an instrument's readings over time, even when conditions are constant.
Hygrometer	An instrument that measures humidity (moisture content) in the air.
Hysteresis	The difference in readings when approaching a value from different directions (e.g., increasing vs. decreasing humidity).
IP Rating	Ingress Protection rating indicating resistance to dust and moisture (e.g., IP65 = dust-tight, protected against water jets).
NIST Traceability	Calibration linked to reference standards maintained by NIST through an unbroken chain of comparisons.
Relative Humidity (RH)	The amount of moisture in the air compared to the maximum amount the air can hold at that temperature, expressed as a percentage.
Resistive Sensor	A humidity sensor that measures changes in electrical resistance caused by moisture absorption.
RTD (Resistance Temperature Detector)	A temperature sensor that measures changes in electrical resistance of a metal (typically platinum) with temperature.
Thermistor	A temperature sensor that measures changes in electrical resistance of a semiconductor with temperature.
Thermocouple	A temperature sensor that measures the voltage generated at the junction of two different metals.
Traceability	The ability to trace a measurement back to a national or international standard through documented calibration.

Timer Terms

Term	Definition
Cycle Timer	A timer that repeats on/off cycles continuously.
Delay Timer	A timer that provides a delay before an output activates (on-delay) or after an input ends (off-delay).
Interval Timer	A timer that provides an output for a set period, regardless of input duration.
On-Delay Timer	A timer that delays the activation of an output after an input is received.
Off-Delay Timer	A timer that delays the deactivation of an output after an input ends.
Process Timer	A timer used to control manufacturing or industrial processes.
Totalizing Timer	A timer that accumulates total time, used for maintenance tracking and production monitoring.

Clock Terms

Term	Definition
Analog Clock	A clock with a traditional dial and hands.
Digital Clock	A clock with a numerical display (LED or LCD).
Master Clock	A central time reference that synchronizes slave clocks in a facility.
NTP (Network Time Protocol)	A protocol for synchronizing clocks over computer networks.
PoE (Power over Ethernet)	Technology that delivers power and data over a single Ethernet cable.
Quartz Movement	A clock movement that uses a quartz crystal to keep time.
Slave Clock	A clock that receives its time reference from a master clock.
Synchronized Clock	A clock that displays the same time as other clocks in a system.

General Terms

Term	Definition
CAGR	Compound Annual Growth Rate—the average annual growth rate over a specified period.
Incoterms	International Commercial Terms defining responsibilities in international shipping.
MOQ	Minimum Order Quantity—the minimum number of units a supplier will accept for an order.
OEM	Original Equipment Manufacturer—a manufacturer that produces products for other companies to brand.
ODM	Original Design Manufacturer—a manufacturer that designs and produces products for other companies to brand.
TCO	Total Cost of Ownership—the total cost of owning and operating an instrument over its life.