I'm confused as how to find the current for a circuit with both parallel and series resistors?
R1 = 2 Ù R2 = 5 Ù R3 = 11 Ù R4 = 10 Ù V = 7 V
R2 and R4 are parallel, then these are in series with R3, then this whole system is in parallel with R1.
I need to find the current through R2. I have found that Req for the whole circuit is 1.755 and the current supplied by the battery is 3.988. I tried to then multiply 3.988 by 3.333 (which is the Req for R2 and R4) to find the voltage drop, 13.29 then divided by R2 of 5 ohms, getting an answer of 2.658.
I have no idea if my strategy is even correct.
FYI - The symbols for ohms didn't work, that's what the U's with accents are.
R2,R4 parallel is 5*10/15=3.33 ohm
in series with R3>>>14.33 ohm
So if 7 volet is across, then half amp through the circuit, it divdes so that 2/3 goes through the five ohm resistor, or I2=2*.5amp/3=1/3 amp. Check my math.
R2 and R4 first
1/Req = 1/5 +1/10 = 3/10
so Req =10/3
add that to R3
10/3 +11 = 43/3
now
1/Rtotal = 1/2 + 3/43 = 49/86
so
Rtotal = 86/49 = 1.755 check
so
i total = 7/1.755 = 3.988 check
However that does not interst me because I want the R2 current
current through R2-R3-R4 branch =
7/(43/3) = 21/43 = .488 amps
voltage drop across R3 = 11*.488
= 5.37 volts
so voltage drop across R2 =7-5.37 = 1.63 volts
so
i = 1.63/5 = .325 amps
Now, when you got that 13.29 volts, you knew something was wrong because it could never be bigger than the 7 volt battery.
thanks for your help!!
To find the current through R2, you correctly calculated the equivalent resistance (Req) for the whole circuit. However, your strategy for finding the voltage drop across R2 and then dividing it by R2 to find the current is not correct.
Here's the correct strategy to find the current through R2 in this circuit:
1. Calculate the total current (I) flowing through the circuit using Ohm's Law: I = V / Req, where V is the battery voltage (7V in this case) and Req is the equivalent resistance of the circuit (1.755 ohms).
In this case, I = 7V / 1.755 ohms = approximately 3.988 amps.
2. Determine the current flowing through the parallel resistors R2 and R4. Since R2 and R4 are in parallel, they have the same voltage drop across them, and the total current (I) is divided between them.
To find the current through R2 and R4, use the formula:
I_parallel = (R2 * I) / (R2 + R4)
I_parallel = (5 ohms * 3.988 A) / (5 ohms + 10 ohms) = approximately 1.329 amps.
Therefore, the current through R2 is approximately 1.329 amps.
It's important to note that the voltage drop across R2 and R4 is not necessary to find the current through R2 in this case. The parallel resistor relationship allows you to directly calculate the current without explicitly determining the voltage drop.