Electrical Units
Convertion table for Electrical Units
Refridgerant - Thermodynamic Units
Convertion table for Refridgerant - Thermodynamic Units
Physical Units
Convertion table for Physical Units
Preffixes |
| |
| Electrical Units |
|
Unit
|
Symbol
|
Measuring
unit
|
Useful
formulae
|
Definition
|
|
Electric
charge
|
q
|
Coulomb
(C)
|
|
It
is -1 for electrons, +1 for protons. The electrical charge of
an object is the sum of the charges of its
particles.
|
|
Alternating
current
|
AC
|
-
|
|
An
electric current that first moves in one direction, then in
the opposite direction with a regular
frequency.
|
|
Direct
current
|
DC
|
-
|
|
An
electrical current that always moves in one
direction.
|
|
Current
intensity
|
I
|
Αmpere
(Α)
|
Ι=dq/dt,
I=V/R
|
The
rate of electric charge flow through a cross-section of a
conductor.
|
|
Potential
difference (voltage)
|
V
|
Volt
(V)
|
V=IR=P/I
|
The
cause for charge flow (electric current) inside a
conductor.
|
|
Electrical
resistance
|
R
|
ohm
(Ω)
|
R=V/I
|
The
property of opposing or reducing electric
current.
|
|
Resistivity
|
ρ
|
Ohm
metre (Ω·m)
|
ρ=RA/l
=1/σ
|
A
measure of how strongly a material opposes the flow of
electric current. (Α:conductor
cross-section area)
|
|
Electric
conductance
|
G
|
siemens
(S)
|
G=1/R=I/V
|
It
is a measure of how easily electricity flows through an
electrical element. The
reciprocal of total electrical resistance.
|
|
Conductivity
|
σ
|
S
m-1=
Ω-1m-1
|
σ=J/E
=1/ρ
|
A
measure of a material's ability to conduct an electric
current.
|
|
Capacitance
|
C
|
Farad
(F)
|
C=Q/V
|
A
measure of the amount of charge stored for a given potential
difference in a conductor
(capacitor).
|
|
Inductance
|
L
|
Henry
(H)
|
L
= Φ/Ι,
πηνίο(coil): L=μrΝ2Α/l
|
The
factor L in the formula of electromotive force
Vαυτ
.
|
|
Period
|
T
|
second
(sec)
|
T=1/f
|
An interval of time
between the recurrence of cycles/phases in a
phenomenon.
|
|
Frequency
|
f
,ν
|
Hertz
(Hz) = cycles per second (1/s), revolution per minute(rpm),
radians per second (rad/s)
|
f=1/T
|
The
number of cycles of a periodic phenomenon per unit of
time.
|
|
Electrical
energy
|
E
|
Joule
(J), kilocalorie (kcal), kilowatts per hour (KWh), peak sun
hours (psh), kilogram
metre (kg.m), British thermal unit
(Btu)
|
|
The
ability to do work, deriving from an electric field or
electric charge flow (electric
current).
|
|
Power
(electrical)
|
P
|
watt,
horse power (hp), kilogram force metres per hour (kg.f m/h),
kilocalories per hour (kcal/h)
|
P=dE/dt=E/t=V2/R=
I2R
|
The
rate at which energy is transferred or the rate at which work
is performed; defined as work per unit of
time
|
|
| Top |
| Convertion table for Electrical Units |
|
Ενέργεια -Energy
|
|
|
J
|
kwh
|
psh
|
hph
|
kg-m
|
kcal
|
Btu (th)
|
|
1 J
|
1
|
2,68.10
|
3,78.10-7
|
3,73.10-7
|
0,1020
|
2,38.104
|
9,48.10-4
|
|
1 kwh
|
3,6.106
|
1
|
1,360
|
1,341
|
3,67.105
|
859,84
|
3413
|
|
1 psh
|
2,65.106
|
0,7355
|
1
|
0,9863
|
2,70.105
|
632,4
|
2510
|
|
1 hph
|
2,68.106
|
0,7457
|
1,014
|
1
|
2,74.105
|
641,2
|
2545
|
|
1 kg-m
|
9,807
|
2,72.10-6
|
3,7.10-6
|
3,65.10-6
|
1
|
2,34.10-3
|
9,29.10-3
|
|
1 kcal
|
4186,8
|
1,16.10-3
|
1,58.10-3
|
1,56.10-3
|
426,9
|
1
|
3,968
|
|
1 Btu (th)
|
1055
|
2,93.10-4
|
3,98.10-4
|
3,93.10-4
|
107,6
|
0,252
|
1
|
|
|
|
|
|
|
|
|
|
|
Ισχύς-Power
|
|
|
|
|
|
Watt
|
hp
|
kg.f m/h
|
kcal/h
|
|
|
|
|
Watt
|
1
|
735,5
|
2,94.10-3
|
1,162
|
|
|
|
|
hp
|
1,36.10-3
|
1
|
4.10-6
|
1,58.10-3
|
|
|
|
|
kg.f m/h
|
367,1
|
27.104
|
1
|
426,66
|
|
|
|
|
kcal/h
|
0,86
|
632,84
|
2,53.10-3
|
1
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Συχνότητα-Frequency
|
|
|
|
|
|
|
Hertz
|
rpm
|
rad/s
|
|
|
|
|
|
1 Hertz
|
1
|
60
|
6,28
|
|
|
|
|
|
1 rpm
|
0,016
|
1
|
0,105
|
|
|
|
|
|
1 rad/s
|
0,159
|
9,549
|
1
|
|
|
|
|
|
| Top |
| Refridgerant - Thermodynamic Units |
|
Unit
|
Symbol
|
Measuring
unit
|
Useful
formulae
|
Definition
|
|
Temperature
|
θ,
T
|
degrees
Celsius (oC),
Fahrenheit (oF), Kelvin
(oK)
|
PV=nRT
|
The property of how "hot"
or "cold" an object is, due to the movement of its
molecules.
|
|
Heat
|
Q
|
Joule
(J), kilogram (large)calorie (kcal), kilowatts per hour (KWh),
peak sun hours (psh), kilogram metre (kg.m), British
thermal unit (Btu)
|
|
A
form of energy, which can be transmitted by contact or
radiation.
|
|
Pressure
/ stress
|
P
|
atmosphere(atm),
technical atmosphere(at), pounds force per
square inch(psi), Pascal (Pa), bar, Torr=mmHg 0oC
(torr)
|
P=F/A,
PV=nRT
|
Force
per unit area.
|
|
Entropy
|
S
|
Joules
per Kelvin (J/K), 1e.u. = 4.184JK ? 1mol ? 1 Joules per kilogram Kelvin (Celsius), kilocalorie per
kilogram Celsius (kg/kgoC), Btu per poun Fahrenheit
(Btu/lboF)
|
dS
= dQ / T
|
The
amount of order or lack of order in a
system.
|
|
Internal
energy
|
U
|
Joule
(J), kilogram (large)calorie (kcal), kilowatts per hour (KWh),
peak sun hours (psh), kilogram metre (kg.m), British
thermal unit (Btu)
|
|
The
total of all the energy in a thermodynamic
system.
|
|
Enthalpy
|
H
|
Kilojoule
per kilogram (kJ/kg), British thermal unit per pound
(Btu/lb)
|
H(S,P)
= U + PV
|
The
sum of the internal energy plus the product of the
pressure times the volume
|
|
Liquid
capacity
|
V
|
Litre
(L), U.S.Fluid ounce(US.fl.oz), Imperial fluid ounce
(Imp.fl.oz), Imp.pint(Imp.pt), U.S.gallon(US.gal), Imperial
gallon(Imp.gal)
|
v=m/ρ
|
The
volume of a liquid in a container
|
|
Viscosity
(absolute)
|
μ
|
Poise(P)
|
|
The
resistance of liquid, due to its flow and the force of
friction between its molecules
|
|
Viscosity
(kinematic)
|
ν
|
Stokes
(St)
|
ν=μ/ρ
|
|
|
| Top |
| Convertion table for Refridgerant - Thermodynamic Units |
|
Θερμοκρασία-Temperature
|
|
|
|
|
|
oC
|
oF
|
oK
|
|
|
|
|
1oC
|
1
|
-17,22
|
274,15
|
|
|
|
|
1oF
|
33,8
|
1
|
255,93
|
|
|
|
|
1oK
|
-272,15
|
-457,87
|
1
|
|
|
|
|
οC=(5oF-160)/9,
oF=9/5 oC+32
|
|
|
|
|
|
|
|
|
|
|
|
|
Πυκνότητα-Density
|
|
|
kg/m3
|
kg/l
|
lb/in3
|
oz/in3
|
oz/gal(US)
|
oz/gal(UK)
|
|
1kg/m3
|
1
|
1000
|
27679,9
|
1730
|
119,826
|
99,77
|
|
1kg/l
|
0,001
|
1
|
27,68
|
1,73
|
0,12
|
0,0998
|
|
1lb/in3
|
3,6.10-5
|
0,036
|
1
|
0,0625
|
4,33.10-3
|
3,6.10-3
|
|
1oz/in3
|
5,78.10-4
|
0,578
|
16
|
1
|
0,069
|
0,058
|
|
1oz/gal(US)
|
0,1335
|
133,53
|
231
|
14,437
|
1
|
0,833
|
|
1oz/gal(UK)
|
0,1604
|
160,36
|
277,4
|
17,339
|
19,215
|
1
|
|
|
|
|
|
|
|
|
|
Πίεση-Pressure
|
|
|
atm
|
at
|
psi
|
torr
|
bar
|
Pa
|
|
1 atm
|
1
|
1,0332
|
14,7
|
760
|
1,0132
|
101325
|
|
1 at
|
0,9678
|
1
|
14,2
|
735,56
|
0,9807
|
98067
|
|
1 psi
|
0,068
|
0,07
|
1
|
51,715
|
0,0689
|
6894,76
|
|
1 torr (mmHg 0oC)
|
1,32.10-3
|
1,35.10-3
|
0,0193
|
1
|
1,33.10-3
|
133,322
|
|
1 bar
|
0,9869
|
1,0197
|
14,504
|
750,06
|
1
|
105
|
|
1 Pa
|
1.10-5
|
1.10-5
|
1,45.10-4
|
7,5.10-3
|
10-5
|
1
|
|
|
|
|
|
|
|
|
Εντροπία-Entropy
|
|
|
|
|
|
|
J/kgoK
|
kcal/kgoC
|
|
|
|
|
|
1 J/kgoK
|
1
|
2,39.10-4
|
|
|
|
|
|
1 kcal/kgoC
|
4186,8
|
1
|
|
|
|
|
|
1 J/kgoK=
1 J/kgoC, 1
kcal/kgoC=1 Btu/lboF
|
|
|
|
|
|
|
|
| Top |
| Physical Units |
|
Unit
|
Symbol
|
Measuring
unit
|
Useful
formulae
|
Definition
|
|
Time
|
t
|
second
(s)
|
|
Fundamental
physical property to distinguish between and produce a
sequence of events.
|
|
Length
(distance, position)
|
l,r,x
|
metre
(m), inch (in/"), foot (ft), mile (mi), yard
(yd)
|
|
The
horizontal distance from one edge to the
other.
|
|
Mass
|
m
|
kilogram
(kg), avoirdupois pound (lb(av)), troy pound (lb t), tonne (t), short ton
(tn(US)), long ton (tn(UK))
|
-
|
The
amount of matter
|
|
Surface
/ area
|
s,A
|
square
metre
(m2), square inch (in2), acre
(ac)
|
s=l2
|
The
outer boundary of an object that distinguishes it from the
space around it.
|
|
Volume
|
V
|
cubic
metre (m3), litre
(lt), cubic foot(ft2), cubic yard(yd3),
(US)gallon
|
v=l3 ,
v=m/ρ
|
The
space a three dimensional object
occupies.
|
|
Angle
|
θ,φ
|
degree(o,
grad) radian(rad)
|
-
|
Part
of area between two rays sharing a common
endpoint.
|
|
Weight
|
B
|
Newton
(N), dyn, pound
force(lbf), kilogram force (kgf), short ton (tn(US)), long ton
(tn(UK))
|
Β=mg
|
The
force on an object due to the gravitational pull of a planet
or other heavenly body.
|
|
Force
|
F
|
Newton
(N), dyn, pound
force(lbf), kilogram force (kgf), short ton (tn(US)), long ton
(tn(UK))
|
F=
dP/dt =m.a
|
The
cause for change in the state of motion, or shape of an
object.
|
|
Specific
weight
|
γ
|
Newton
per square metre (N/m3).
|
γ=ρ.g
|
The
weight per unit volume of a
material.
|
|
Torque,
moment
|
τ
|
Newton
metre (Nm)
|
τ
= r x F = r.d
|
Product
of force times
the moment arm.
|
|
Momentum
|
P,J
|
kg.m/s
|
P=m.υ
|
The
product of object's mass and
velocity.
|
|
Angular
momentum
|
L
|
Joule
second (J.s)
|
L=
ω.Ι
|
The product of angular
velocity ω
and the moment of inertia Ι
of a rotating body.
|
|
Moment
of inertia
|
Ι
|
kg.m2
|
|
The
tendency of an object to resist a change in its state of
motion.
|
|
Density
|
ρ
|
kilogram
per cubic metre (kg/m3)
|
ρ=m/V
|
The
compactness of matter described by a ratio of mass (or weight)
per unit volume
|
|
Velocity
|
υ
|
metres
per second (m/s), kilometres per hour (km/h), inces per second
(in/s), miles per hour (mph)
|
υ=dx/dt
|
Measure
of how fast an object moves - the rate of change of position
per change in time
|
|
Angular
velocity (speed)
|
ω
|
radians
per second (rad/s), revolutions per minute
(rpm)
|
ω=dφ/dt
|
Describes
rotational velocity referring to the angle covered by the
rotating body.
|
|
Acceleration
|
a
|
metres
per square second (m/s2), kilometres per sq hour
(km/h2), inches per sq second (in/s2),
miles per sq hour (mi/h2),
|
a=dυ/dt=F/m
|
The
rate of change of velocity per change in
time
|
|
Energy
|
E
|
Joule
(J=kg.m2/s2), calorie (cal),
kilowatt/hour (KWh), erg, electronvolt
(eV)
|
E=1/2mυ2=mgr
|
The
ability to do work. There are five forms of energy-mechanical,
chemical, radiant, electrical, and
nuclear
|
|
| Top |
| Convertion table for Physical Units |
|
Βάρος[=δύναμη]-Weight[=Force]
|
|
|
|
|
N
|
lbf
|
kgf
|
tn(UK)
|
tn(US)
|
|
|
|
1 Ν
|
1
|
0,225
|
980665
|
9964
|
8896,4
|
|
|
|
1lbf
|
4,448
|
1
|
2,205
|
2240
|
2000
|
|
|
|
kgf
|
9,81
|
0,454
|
1
|
1016
|
907,2
|
|
|
|
tn(UK)
|
9964
|
4,46 .10-4
|
0,001
|
1
|
0,893
|
|
|
|
tn(US)
|
9806,7
|
5 .10-4
|
0,001
|
1,12
|
1
|
|
|
|
1kg f=0,001tonne f
1N = 105 dyn
|
|
|
|
|
|
|
|
|
|
|
|
|
Μάζα-Mass
|
|
|
|
|
kg
|
lb (lb(av))
|
lb t
|
sh.tn(US)
|
lg.ton (UK)
|
oz |
|
|
1 kg
|
1
|
2,205
|
2,68
|
0,0011
|
9,84.10-4
|
35,2733 |
|
|
1 lb (lb(av))
|
0,4536
|
1
|
0,823
|
0,0005
|
4,46.10-4
|
16
|
|
|
1 lb t
|
0,3732
|
1,215
|
1
|
2430,5
|
2722,2
|
12
|
|
|
1 sh.ton(US)
|
907,2
|
2000
|
4,11.10-4
|
1
|
0,8929
|
0,03888 |
|
|
1 lg.ton(UK)
|
1016
|
2240
|
3,67.10-4
|
1,12
|
1
|
0,034719 |
|
|
1 oz |
0,02835 |
0,0625 |
0,08333 |
25,719 |
28,803 |
1
|
|
|
1lb = 16 oz
1kg=1000g 1m.ton=1000 kg
1lb(av)=16 oz(av) 1lb(t)=12 oz(t)
|
|
|
|
|
|
|
|
|
|
|
|
|
Μήκος-Length
|
|
|
cm
|
m
|
km
|
in
|
ft
|
yard
|
mile
|
|
1 cm
|
1
|
0,01
|
106
|
0,3937
|
0,0328
|
1,09.10-2
|
6,21.106
|
|
1 m
|
100
|
1
|
0,001
|
39,37
|
3,281
|
1,094
|
6,21.10-4
|
|
1 km
|
1.105
|
1000
|
1
|
3,94.104
|
3281
|
1094
|
0,6214
|
|
1 in
|
2,54
|
0,0254
|
2,54.10-5
|
1
|
0,0833
|
0,0278
|
1,58.10-5
|
|
1 ft
|
30,48
|
0,3048
|
3,05.10-4
|
12
|
1
|
0,333
|
1,89.10-4
|
|
1 yard
|
91,44
|
0,9144
|
9,14.10-4
|
36
|
3
|
1
|
5,68.10-4
|
|
1 mile
|
1,61.105
|
1609
|
1,609
|
6,34.104
|
5280
|
1760
|
1
|
|
1yd=3ft=36in
|
|
|
|
Επιφάνεια-Area
|
|
|
|
cm2
|
m2
|
km2
|
in2
|
ft2
|
mi2
|
|
|
1 cm2
|
1
|
1.10-4
|
1.10-10
|
0,155
|
10,8.104
|
3,86.10-11
|
|
|
1 m2
|
104
|
1
|
1.10-6
|
1550
|
10,76
|
3,86.10-7
|
|
|
1 km2
|
1010
|
1.106
|
1
|
1,55.109
|
1,08.107
|
0,3861
|
|
|
1 in2
|
6,452
|
6,45.10-4
|
6,45.10-8
|
1
|
6,94.10-3
|
2,49.10-10
|
|
|
1 ft2
|
928,8
|
0,0929
|
9,29.10-6
|
144
|
1
|
3,59.10-8
|
|
|
1 mi2
|
2,59.1010
|
2,59.106
|
2,59
|
4,01.109
|
2,79.107
|
1
|
|
|
1mi2 =
640ac 1km2=247,1ac
|
|
|
|
|
|
|
|
|
|
|
|
Όγκος-Volume
|
|
|
|
cm³
|
lt=dm³
|
m³
|
in³
|
ft³
|
yd³
|
|
|
1cm³
|
1
|
0,001
|
1.106
|
0,061
|
3,53.105
|
1,31.106
|
|
|
lt=dm³
|
1000
|
1
|
0,001
|
61,02
|
0,035
|
1,31.103
|
|
|
1m³
|
1.106
|
1000
|
1
|
6,1.104
|
35,31
|
1,308
|
|
|
1in³
|
16,39
|
0,0164
|
1,64.10-5
|
1
|
5,79.10-4
|
2,14.105
|
|
|
1ft3
|
2,83.104
|
28,32
|
0,0283
|
1728
|
1
|
0,037
|
|
|
1yd³
|
7,65.105
|
764,5
|
0,7645
|
4,67.104
|
27
|
1
|
|
|
|
|
|
|
|
|
|
|
|
Ταχύτητα-Speed
|
|
|
|
m/s
|
cm/sec
|
km/hr
|
in/sec
|
ft/min
|
mph
|
|
|
1 m/s
|
1
|
|
|
|
|
|
|
|
1 cm/sec
|
100
|
1
|
0,036
|
0,3937
|
1,968
|
0,0224
|
|
|
1 km/hr
|
3,6
|
27,78
|
1
|
10,94
|
54,68
|
0,6214
|
|
|
1 in/sec
|
39,37
|
2,54
|
0,0914
|
1
|
5
|
0,0568
|
|
|
1 ft/min
|
196,85
|
0,508
|
0,0183
|
0,2
|
1
|
0,0114
|
|
|
1 mph
|
2,24
|
44,7
|
1,609
|
17,6
|
88
|
1
|
|
|
|
|
|
|
|
|
|
|
|
Επιτάχυνση-Acceleration
|
|
|
|
m/s2
|
cm/s2
|
km/s2
|
in/s2
|
ft/s2
|
mi/s2
|
|
|
1 m/s2
|
1
|
0,1
|
0,001
|
39,37
|
3,28
|
6,2.10-4
|
|
|
1 cm/s2
|
0,01
|
1
|
1.10-5
|
0.39
|
0,033
|
6,2,10-6
|
|
|
1 km/s2
|
1000
|
100000
|
1
|
39370
|
3280
|
0,621
|
|
|
1 in/s2
|
0,0254
|
2,54
|
2,54.10-5
|
1
|
0,083
|
1,58.10-5
|
|
|
1 ft/s2
|
0,305
|
30,48
|
3.05.10-4
|
12
|
1
|
1,9.10-4
|
|
|
1 mi/s2
|
1609,34
|
160934,4
|
1,609
|
63360
|
5280
|
1
|
|
|
|
|
|
|
|
|
|
|
|
Χωρητικότητα-Capacity
|
|
|
|
L
|
US.fl.oz
|
lmp.fl.oz
|
lmp.pint
|
US.gal
|
1 lmp.gal
|
|
|
1 L
|
1
|
33,81
|
35,3
|
1,76
|
0,2642
|
0,22
|
|
|
1 US.fl.oz
|
0,0296
|
1
|
1,041
|
0,052
|
0,0078
|
0,0065
|
|
|
1 lmp.fl.oz
|
0,0284
|
0,9607
|
1
|
0,05
|
0,0075
|
0,0062
|
|
|
1 lmp.pint
|
0,5682
|
19,21
|
20
|
1
|
0,1501
|
0,125
|
|
|
1 US.gal
|
3,785
|
128
|
133,2
|
6,662
|
1
|
0,8327
|
|
|
1 lmp.gal
|
4,546
|
153,7
|
160
|
8
|
1,201
|
1
|
|
|
|
|
|
|
|
|
|
|
|
Χρόνος-time
|
|
|
|
|
1y=365d, 1d=24h, 1h=60min, 1min=60s
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Γωνία-Angle
|
|
|
|
|
|
|
degree(o)
|
rad
|
grad
|
|
|
|
|
|
1 degree(o)
|
1
|
0,017
|
1,111
|
|
|
|
|
|
1 rad
|
57,296
|
1
|
63,662
|
|
|
|
|
|
1 grad
|
0,9
|
0,016
|
1
|
|
|
|
|
|
1o= 0,017
rad, 360o=2π rad
|
|
|
|
|
|
| Top |
| Preffixes |
|
10n
|
prefix
|
symbol
|
|
1012
|
tera
|
T
|
|
109
|
giga
|
G
|
|
106
|
mega
|
M
|
|
103
|
kilo
|
k
|
|
102
|
hecto
|
h
|
|
101
|
deca
|
da
|
|
10-1
|
deci
|
d
|
|
10-2
|
centi
|
c
|
|
10-3
|
milli
|
m
|
|
10-6
|
micro
|
μ
|
|
10-9
|
nano
|
n
|
|
10-12
|
pico
|
p
|
|
| Top |
|
|