View Full Version : Series- parallel circuit
MrSan93
Aug 16, 2014, 06:35 AM
View image: aa (http://postimg.org/image/fs7mgby6r/)
How to calculate the total resistance?
Can anyone help kind of confused here
wrazouk
Aug 16, 2014, 06:55 AM
You can replace R1, R2 by a resistance (name it R') with value R' = R1//R2.
The same thing for R3, R4, R''=R3//R4.
Now you have R' in series with R'', i.e: total resistance R = R'+R''=(R1//R2)+(R3//R4).
hkstroud
Aug 16, 2014, 07:07 AM
First find resistance of the resistors in parallel.
Find resistance of R1 and R2 in parallel.
(R1 X R2) / (R1 + R2) = RP1.
Find resistance of R3 and R4 in parallel.
(R3 X R4) / (R3 + R4) = RP2.
Then you have a series circuit. With a series circuit you simply add all the resistance for total circuit resistance.
RP1 + RP2 = Total circuit resistance
ebaines
Aug 16, 2014, 09:05 AM
hkstroud - you need to learn to use parentheses. What you wrote is this:
R_1 \times \frac {R_2}{R_1} + R_2 = RP_1
which is equivalent to:
2R_2 = RP_1
and that's clearly incorrect.
What you should have written is:
R 1 x R2/(R1+R2) = RP1, or
\frac {R_1 R_2}{R_1 + R_2} = RP_1
To the the OP: hope this helps.
hkstroud
Aug 16, 2014, 03:57 PM
Is that better?
ebaines
Aug 18, 2014, 05:41 AM
Is that better?
Much!