Circuit Question?

Question

I have two 8Ω resistors in series with two 33Ω resistors in parallel. (3-V power source)
a.) How much current flowing across each resistor?
b.) What is the voltage across each resistor?
Thanks

Answer 1

Step 1:
Find the total resistance in the circuit:
8 Ohms + 8 Ohms + 33 Ohms / 2 = 32.5 Ohms

Step 2:
Find the total current in the 3V power source.
Use Ohms law:
3volts = current * 32.5 Ohms
3 volts / 32.5 Ohms = current = 92.3 milliAmps

Step 3:
Find the current in each resistor:
92.3 milliamps is the current flowing through the 8 Ohm resistors. That current is split in 2 for each of the 33 Ohm resistors (46.1 milliAmps each).

Step 4:
Find the voltage across each resistor:
Use Ohms law:
Voltage = 8 * 92.3 mA for the 8 Ohm resistors
Voltage = 33 * 46.1 mA for the 33 Ohm resistors.

.

Answer 2

Take it one part at a time. The two 8ohms in series are added together so 16 ohms. The two 33 ohm resisters in parallel you would use the equation R = 1/(1/R1 + 1/R2) = 1/(1/33 + 1/33) = 1/(2/33) = 16.5 ohms (since they are the same size you can just divide 33 by two but that formula will work for any two resistors) Now you combine the two partial results 16 ohms in series with 16.5 ohms. 16 + 16.5 = 32.5 ohms.

The total current is I = E/R = 3/32.5 = 0.0923 amps.

This is the current flowing thru each of the 8 ohm resistors.

Using E = I*R = 0.0923 * 8 = 0.7385 Volts across each of the 8 ohm resistors.

The current thru the combination of the two 33's in parallel (16.5 ohms) is also 0.0923 amps. Using E = I*R - 0.0923 * 16.5 = 1.523 Volts.

Finally the current thru each of the 33 ohm resistors can be found using I = E/R = 1.523 / 33 = 0.04615

You can check your work. Adding up the voltages should sum to zero +3 (source) - 0.7385 - 0.7385 - 1.523 = 0

You use two things to solve this. Ohm's law and Kirchhoff's Laws. If you understand them DC circuit analysis is easy!

Answer 3

8+33=41
two 41 in parallel 20.5

a) Current does not flow across a resistor, so the answer is none

the current in or through each resistor is 3/41
= 73.17mA

the voltage across the two 8 Ohms is 585.37mV

the voltage across the two 33 Ohms is 2.415 V


assuming I have the same circuit as you

IF on the other hand we punctuate your question we get another circuit

then we have

16+33/2= 32.5 Ohms


= 92.31mA (in both of the Ohms)

Voltage across each of the 8 Ohms is 738.46mV


Half the current in each of the 33 Ohms (46.15mA)
and voltage across each of the 33 Ohms is 1.523 Volts