1 coulomb is equivalent to 6.24 × 10^18 electrons.
2 cm H2O.
Force = mass × acceleration (F = ma).
1 cycle per second.
The energy a body possesses because of its motion.
The lowest possible temperature where nothing could be colder and all thermal motion stops, precisely 0 K or -273.15 °C.
137 bar.
An under-damped system changes quickly in response to input, overshooting and oscillating around the true value before settling.
The temperature above which a gas cannot be liquefied by pressure alone.
SI units.
Around 45,000 Hz.
In a critically damped system, D = 1.
Initially, the gauge pressure remains constant until all the liquid is used up, after which it declines over time following Boyle's law.
Seven base units.
It is the parameter chosen to be measured, e.g., blood pressure (BP).
Weigh the cylinder to find the weight of remaining N2O, then apply Avogadro’s hypothesis: Volume of N2O (L) = (Cylinder weight - Tare weight) / Molecular weight of N2O × 22.4 L.
Hysteresis occurs when the output of the system alters depending on whether the input is rising or falling.
The force from the spring against the force generated by pressure against the diaphragm.
Input, Transducer, Transmission path, Conditioning unit, Display unit, Output.
It increases damping but decreases the system's natural frequency significantly.
Damping describes the resistance of a system to oscillation resulting from a change in the input.
It converts one form of energy into another, e.g., a strain gauge in blood pressure monitoring.
During the eighteenth-century French revolution.
P1 × v1 = P2 × v2.
An over-damped system has damping greater than critical, potentially changing so slowly that it never reaches the true value.
A substance that is above its critical temperature and will expand to fill any available space.
Blood pressure is a gauge pressure.
36.5 °C.
Kilogram (kg).
Surface tension can lead to over-readings in water manometers and under-readings in mercury manometers.
It contains a larger diaphragm that operates a valve connecting it to the first-stage low-pressure chamber.
PV = Constant or P ∝ 1/V.
Resonance is the tendency of a system to oscillate at maximum amplitude at certain frequencies, determined by the mass and stiffness of the system.
It may overshoot in its reading.
0.75.
Hecto (h).
It explains how a sudden expansion of gas through a probe results in a very cold tip, used to freeze lesions.
The potential difference between two points of a conducting wire when 1 joule of work is done to move 1 coulomb of charge between them.
Up to 1500 liters of liquid oxygen.
The force required to accelerate a 1 kg mass at a rate of 1 m/s².
Partial pressure is the pressure exerted by an individual gas, while total pressure is the sum of all partial pressures in a mixture.
A high-pressure chamber and a low or control pressure chamber.
Pressure measurements above or below atmospheric pressure; an empty cylinder has a gauge pressure of zero.
It allows conversion between different sets of conditions for a given mass of gas.
By the thermal decomposition of ammonium nitrate.
Kilogram per cubic metre (kg/m³).
They consist of a fluid-filled column open to the atmosphere, measuring gauge pressure based on fluid height, density, and gravitational force.
A demand valve on an entonox cylinder or diving cylinder.
Plane angle (radian) and solid angle (steradian).
Noise can be reduced by adding filters, such as high pass, low pass, and notch filters, or by averaging out repetitive signals.
The pressure within the second-stage chamber reduces, moving the diaphragm and opening the valve to allow gas to enter.
It consists of a coiled metal tube that changes shape under pressure, moving a pointer across a scale.
Zeolite adsorbents.
-5.5 °C.
It turns into a solid.
Between −150 and −170 °C.
At constant pressure, the volume of a given mass of gas is directly proportional to the absolute temperature.
PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the universal gas constant, and T is temperature.
The mass of water vapor present in a particular sample of air at a given temperature, measured as kg m–3.
Pressure measurements that include atmospheric pressure; it is gauge pressure plus atmospheric pressure.
The diaphragm will lift, causing the conical valve to shut.
Metre (m).
Calibration should be performed after a predetermined time, after a set number of uses, when unexpected results occur, or if the machine is moved or damaged.
52 bar.
At constant temperature, the absolute pressure of a given mass of gas is inversely proportional to its volume.
0.67.
Analogue systems have continuous output signals, while digital systems have discontinuous output signals.
Blue/Blue.
Adding energy at the right moment increases the amplitude of oscillations, which can interfere with the output reading.
Kilogram.
Mega (M).
Force is a vector quantity that can cause an object with mass to accelerate, defined by Newton's second law as mass multiplied by acceleration.
The newton (N).
In a gas mixture, the pressure exerted by each gas is equal to the pressure it would exert if it occupied the container alone.
Joule per kelvin.
13,800 kPa (gauge pressure + atmospheric pressure).
The mass of water in a given volume of air, expressed as a percentage of the maximum mass of water that the air could hold at the given temperature.
The property of a conductor to oppose the flow of current through it, with the derived SI unit being the Ohm (Ω).
At constant volume, the absolute pressure of a given mass of gas varies directly with the absolute temperature.
At standard temperature and pressure, 1 mole of gas occupies 22.4 L.
−119 °C.
Cubic metre (m³).
It unites Charles's Law, Gay-Lussac's Law, and other gas laws under one equation.
It should have a short, stiff, wide cannula, no connections, and no air bubbles to maintain high natural frequency.
Metre per second (m/s).
Damping is the result of frictional forces working in that system.
Second (s), defined by the frequency of radiation emitted by caesium-133 in its ground state.
Units formed by combination of various base units according to mathematical relationships.
It has a Torricellian vacuum above mercury, measuring pressure based on the height of the mercury column.
It states that the total pressure exerted by a gaseous mixture is equal to the sum of the partial pressures of each individual gas.
How closely the output reflects the true value being measured.
The temperature above which a gas cannot be liquefied by pressure alone.
It is the movement of the output away from the true input value, usually caused by changing properties of the equipment.
To prevent variable flow of gas or vapour to the patient due to high pressures and surges.
Tera (T).
A 2 mL syringe generates higher pressure due to its smaller cross-sectional area, making it more effective for dislodging blockages.
1 Pa is the force of 1 N acting over 1 m².
The energy released or absorbed by a substance when it changes phase at a given temperature.
Around 20 Hz.
It reduces the natural frequency from 45,000 Hz to around 15 Hz.
Under-damping, leading to falsely elevated and depressed peaks and troughs in the output display.
Calibration is a process in which the output of a measuring device is compared to a standard of known units of measure to determine its accuracy.
It states that equal volumes of gases at a given temperature and pressure contain the same numbers of molecules.
273.15 K and 101.3 kPa.
Because if the temperature falls below -5.5 °C, a liquid mixture can form, affecting the gas mixture delivered to patients.
The pressure exerted by a vapour in contact with and in equilibrium with its liquid phase within a closed system at a given temperature.
It carries the electrical signal to the conditioning unit.
By storing them horizontally at temperatures above 5 °C.
Devices that reduce a higher variable inlet pressure to a constant lower outlet pressure.
Because gauge pressures reflect the saturation vapor pressure of N2O above its liquid, which varies with temperature.
The unit of charge, defined as the amount of charge passing a given point per second when 1 A of current is flowing.
Over 99% pure.
Vapour.
The temperature at which the liquid and solid phases of a substance are in equilibrium at a given pressure.
Pressure regulators, flow restrictors, and pressure relief valves.
One newton is equivalent to a 102 g weight due to gravity's acceleration of 9.81 m/s².
The resistance between two points of a conductor when a constant potential difference of 1 volt applied between them produces a current of 1 ampere.
Partial pressures of gases, including oxygen, fall with increasing altitude.
The metre and kilogram.
m² (square metre).
Friction in the measurement system.
Because it exhibits hysteresis due to the elastic energy stored within it.
A gas that is below its critical temperature.
Inappropriately over-represented arterial pressure readings.
By using the formula: No. of moles of N2O = (Cylinder weight - Tare weight) / Molecular weight of N2O.
The temperature at which a mixture of gases may separate into individual constituents.
The amount of energy required to increase the temperature of 1 g of water by 1 °C, equivalent to 4.16 J.
Using the ideal gas law and the absolute pressure of the cylinder.
A regulator where the cylinder pressure opens the valve.
Joule (J).
The amount of heat required to convert a unit mass of a liquid at its boiling point into vapor without an increase in temperature.
Milli (m).
Pascal (N/m²).
Watt (W), defined as 1 joule per second.
Momentum is calculated as mass multiplied by velocity.
4 bar (400 kPa).
The energy of a body or system as a result of its position in an electric, magnetic, or gravitational field.
The work done when applying a force of 1 newton through a distance of 1 meter.
A critically damped system has a longer response time than an under-damped system, with no significant overshoot and minimal oscillations.
The universal gas constant, which is approximately 8.32144 J/(K·mol).
In a system without hysteresis, the output can be predicted from the input alone.
An optimally damped system accepts some oscillations and overshoot to achieve a faster response time, with 64% of energy removed (D = 0.64).
Ampere (A), which is the current that produces a force of 2 × 10–7 newtons per meter between two parallel wires in a vacuum.
52 bar.
The temperature above which a substance cannot be liquefied, regardless of the pressure applied.
Metre per second squared (m/s²).
Barometers measure absolute pressure and are closed to the atmosphere.
The amount of energy required to raise the temperature of 1 kg of a substance by 1 °C.
Second (s).
The amount of heat required to convert a unit mass of a solid at its melting point into a liquid without an increase in temperature.
It may never reach the new elevated input value or take too long to be useful.
A regulator where the output of one stage is the input of another, reducing wear and pressure fluctuations.
Unlike weight, mass does not alter under conditions of differing gravity.
Micro (μ).
A quantity containing the same number of particles as there are atoms in 12 g of carbon-12, which is 6.022 × 10^23 (Avogadro's constant).
By weighing the storage vessel.
The negative logarithm to the base 10 of the hydrogen ion concentration in a solution.
The rate of doing work, with the unit of power being the watt (1 watt = 1 joule per second).
Kelvin (K).
A substance that exists above its critical temperature.
By a spring connected to a diaphragm in the control chamber.
1370 L of O2 is available.
A theoretical gas where molecules behave as individual particles moving randomly, independent of each other.
It refers to the liquefaction and separation of individual gas components in a mixture when exposed to temperatures below its pseudocritical temperature.
It can fix or vary the pressure in the control chamber by altering its tension.
Air bubbles are compressible and decrease energy transmission, resulting in a damped trace.
A liquid mixture containing mostly N2O with about 20% O2 can form, leading to a hypoxic gas mixture being delivered to patients.
P1V1/T1 = P2V2/T2.
The electrical signal is processed, analyzed, and passed to the display unit.
Candela (cd), defined as the luminous intensity of a source emitting monochromatic radiation of frequency 540 × 10^12 hertz.
Greater mass results in slower oscillations, while greater stiffness leads to faster oscillations.
The amount of heat required to convert a unit mass of a liquid at its boiling point into a gas without an increase in temperature, at a given pressure.
Rapid compression raises the temperature, while sudden expansion lowers it.
A regulator where the output of one valve is dependent on the output of another.
A vacuum-insulated evaporator (VIE).
Newton (N).
1 N is the force required to accelerate a mass of 1 kg by 1 m per second squared.
The amount of heat required to raise the temperature of an object by 1 °C.
Using at least two standards increases the accuracy of the resultant measuring device.
6.022 × 10^23 particles, which is the number of particles in one mole of a substance.
A set of rules governing the relationship between thermodynamic temperature, volume, and pressure of ideal gases.
Signal noise describes unwanted external information that alters the output of a transducer.
Force per unit area; the SI unit is the pascal (N/m²).
-119 °C.
They measure high pressures where manometers would be impractical.
It states that the amount of gas dissolved in a liquid is proportional to its partial pressure above that liquid at a given temperature.
It determines how small a change in input will result in a change in output.
A substance in the gas phase below its critical temperature.
Metre (m).
That which changes a body’s state of rest or motion.
Molybdenum steel cylinders (size E cylinders).
The temperature at which the vapor pressure of a liquid equals the surrounding ambient pressure, causing the liquid to change into vapor.
Response time is the time taken for the output to reach 90% of its final reading.
The pressure required to liquefy a gas at its critical temperature.
N/m² (newton per square metre).
Fractional distillation of liquefied air.
A regulator where a spring opens the valve in response to falling outlet pressure.
The temperature and pressure at which water exists in equilibrium as liquid, solid, and vapour; temperature = 0.01 °C or 273.16 K, pressure = 0.006 atm or 611.73 pascals.
90–93% pure.
Brown/Brown & White.
The gravitational force acting on an object, measured in newtons; weight = mass in kg × gravitational acceleration (9.81 m/s²).
No, atmospheric pressure varies with altitude and temperature.
Force per unit area, with the derived SI unit being the Pascal (Pa).
Because liquids are less compressible than gases, preventing explosions at high temperatures.
Newton (N).
Rise time is the time taken for the output to rise from 10 to 90% of its final reading.
4.16 kJ/kg °C.
Kelvin (K).
137 bar.
Pressure is the force applied per unit area.
The degree of amplification of the measurement system, or the output to input ratio.
As the length of the path travelled by light in vacuum during the time interval of 1/299,792,458 of a second.
7 bar.
One of the four fundamental states of matter, distinguished by vast separation between individual particles.
The ideal gas law.
1/273.16 of the thermodynamic scale temperature of the triple point of water.
Because cylinder technology originally measured filling pressures in psi, equivalent to 2000 psi.
