Centigrade Fahrenheit
Conversion of Centigrade (Celsius) Fahrenheit Temperature
Electricians select conductors and other equipment based on the temperature
where they are to be installed. There are times when one temperature scale needs
to be converted to the other. Here is the calculator technique to accomplish
this conversion:
In the formulas below, / represents division, * represents multiplication, 
subtraction, + addition and = is equal.
Tc = (5/9)*(Tf32); Tc = temperature in degrees Celsius, Tf = temperature in
degrees Fahrenheit
For example, suppose you have a Fahrenheit temperature of 98.6 degrees and you
wanted to convert it into degrees on the Celsius scale. Using the above formula,
you would first subtract 32 from the Fahrenheit temperature and get 66.6 as a
result. Then you multiply 66.6 by fiveninths and get the converted value of 37
degrees Celsius.
Below is the formula to convert a Celsius scale temperature into degrees on the
Fahrenheit scale.
Tf = (9/5)*Tc+32; Tc = temperature in degrees Celsius, Tf = temperature in
degrees Fahrenheit
Assume that you have a Celsius scale temperature of 100 degrees and you
wish to convert it into degrees on the Fahrenheit scale. Using the stated
formula, you first multiply the Celsius scale temperature reading by ninefifths
and get a result of 180. Then add 32 to 180 and get the final converted result
of 212 degrees on the Fahrenheit scale.
Below is another accepted conversion method that works just as well and perhaps
might be easier to remember. No matter which direction you want go, from
Fahrenheit to Celsius or Celsius to Fahrenheit, always first add 40 to
the number. Next, multiply by 5/9 or 9/5 just like the first method. Then,
always subtract out the 40 you just added to yield the final result. To remember
whether to use 5/9 or 9/5 when converting from Fahrenheit to Celsius or
Celsius to Fahrenheit, just simply remember, F (for Fahrenheit)
begins with the same letter as Fraction. 5/9 is always a Fraction;
while 9/5 is also a fraction, in this form, it is Clearly a whole
number plus a fraction (1 and 4/5). Thus, if you want to convert Fahrenheit
(F) to Celsius (C), then use the Fraction 5/9; Celsius (C)
to Fahrenheit (F), use the other, 9/5, which is Clearly not just a
fraction.
For an example of this method, we'll use the values we used in the initial
example, 98.6 F and 37 C, which are equal.
To convert from F to C, try these calculations manually.
98.6 + 40 = 138.6, and 138.6 * 5/9 = 77. For the final calculation, remove the
40. 77  40 = 37
To convert from C to F, try these calculations manually.
37 + 40 = 77, and 77 * 9/5 = 138.6. For the final calculation, remove the 40.
138.6  40 = 98.6
In summary, add 40, (F to C) multiply by Fraction...(C to
F) multiply by the other, subtract 40.
The Celsius temperature scale is still sometimes referred to as the
"centigrade" scale. Centigrade means "consisting of or divided
into 100 degrees;" the Celsius scale, devised by Swedish Astronomer Andres
Celsius (17011744) for scientific purposes, has 100 degrees between the
freezing point (0 C) and boiling point (100 C) of pure water at sea level air
pressure. The term Celsius was adopted in 1948 by an international conference on
weights and measures.
Here is a chart which makes calculations unnecessary unless extreme accuracy
is important.
REFERENCE TABLE
CELSIUS/CENTIGRADE 
FAHRENHEIT 
40
deg. 
40
deg. 
17.8
deg. 
0
deg. 
 10
deg. 
14
deg. 
0
deg. 
32
deg. 
5
deg. 
41
deg. 
10
deg 
50
deg. 
15
deg. 
59
deg. 
20
deg. 
68
deg. 
25
deg. 
77
deg. 
30
deg. 
86
deg. 
35
deg. 
95
deg. 
40
deg. 
104
deg. 
50
deg. 
122
deg. 
60
deg. 
140
deg. 
70
deg. 
158
deg. 
80
deg. 
176
deg. 
90
deg. 
194
deg. 
100
deg. 
212
deg. 
More
Conversion from one temperature scale Celsius (Centigrade) to Fahrenheit, or
back, is not a task an electrician typically performs. But it is included here
as a type of calculator practice problem.
If you know Centigrade degrees C and want to find Fahrenheit degrees F, here
is he formula:\
degrees F = 9/5 degrees C + 32
On the calculator:
Clear 9 / 5 x degrees C = + 32 = read answer
If you want Fahrenheit degrees F and want to find Centigrade degrees C, here
is the formula:
degrees C = 5/9 (F  32)
On the calculator:
Clear 5 / 9 x ( degrees F  32) = read answer
Where a parenthesis occurs in a formula, ( or ), pay attention to if it is a
left ( or a right ) parenthesis. There are even times when making electrical calculations
where more than one set of parenthesis are included in a formula. Just enter
then as you come to them. Let the calculator worry about keeping them straight.
Find practice problems HERE.
Find audio support HERE.
