resistor in parallel

[searley]

two resistors of 1 ohm & 2 ohms in parallel across a 50v.total current in the circuit ?

i now the answer is 75.8amps.what i cant work out is how to get the 0.66 of the 1 & 2 ohm when added together ?

thanks for looking.Guiness Drink

 

[Andy™]

you dont add them together

not sure how to get fractions to work on here... so come back in 10 mins

 

[springcrocus]

R1 x R2 / R1 + R2

 

[Andy™]

EDIT: kinda messed up with my maths.

now edited

 

[Andy™]

R1 x R2 / R1 + R2

will have to remember that... much easier than my way!

 

[oliver1234]

Just a litle tip but worth remembering (for me at least), when calculating resitors in parallel the total value is always smaller than the smallest single resistor.

It can help you if you do the maths in your head and forget where the decimal point goes.

 

[septiclecky]

will have to remember that... much easier than my way!

Only works for 2 resistors though

 

[Theorysparky]

1/1 + 1/2 = 1/RT

= 0.67ohms

This is good for any number of resistors in parallel

Searley

did we not cover this in an earlier lesson ????

Electrician Forum

:x

 

[seajayess]

easiest way is to divide 1 by the resistance of each resistor then add the results all together, then with the sum of the results divide 1 by the sum of your results this will give you the total resistance of resistors in parallel.

2 Ohms/ 6 Ohms/ 8 Ohms/ 7 ohms

1 Div 2 = .5 1 Div 6 = .167 1 Div 8 = .125 1 Div 7 = .148

.5+.167+.125+.148 = .94

1 Div .94 = 1.064

Total Resistance 1.064 ohms

Hopes this makes sense CJS