Series and Parallel Resistor

[jam7cacci]

hi! I need some assistance regarding my assignment. hope there's anyone who could help me out. the questions are:

1.a. a 12 ohms resistor is connected in parallel with a series combination of resistors of 8 ohms and 16 ohms. if voltage drop across the 8 ohms resistor, is 48 volts. Determine the total impressed voltage and total current. Vt=? It=?


1.b. Relevant equations
V = IR; I=V/R



1.c. The attempt at a solution
so... first i have to get the total resistance to get the total current and voltage right? (Please correct me if I'm wrong. thanks! :D)

R12 = 8ohms + 16ohms = 24ohms

1/RT = 1/R12 + 1/R3
1/RT = 1/24 + 1/12ohms
1/RT = 1/8 ohms

Rt = 8 ohms


here's the part where I'm totally confused
It = Vt/Rt
It = 48Volts / 8 ohms
It = 6 A

Vt = 48? (i really don't know how to solve for the total voltage)



2.a. 2 resistors 1.95ohms and 0.05ohms are connected in parallel and takes a total current of 50V. What is the current in each resistor?


2.b. Relevant equations
I1 = It

I1 = V1/R1



2.c. The attempt at a solution

I1 = 50V / 1.95ohms
I1 = 25.64 A

I2 = 50V / 0.05ohms
I2 = 1000 A

 

[edmondng]

voltage is the same for all when in parallel
current is the same for all when in series.
(ie: when you use the meter to emasure voltage, you put the probe across 2 points hence the probe is in parallel with component, but when you measure current you cannot do the same, need to make it part of the circuit)

for first part, find voltage drop across 8 and 16, then voltage across both of that is same as 12ohm (ie: if 48v across 8 ohm, and since 8 ohm in series with 16 and they share same current, how much is voltage across 16ohm, then what is the total voltage across 8series16, this is your answer)
for 2nd, you need to find the equivalent resistance, then find current

for 2nd, how does it take total current 50V? you mean 50A? do a current divider
least resistance means more current flow in that direction

 

[ravenprp]

Hello! I would be happy to assist you with your assignment.

1. For part 1.a, you are correct in calculating the total resistance by adding the resistances in parallel first and then adding that to the series combination of resistors. However, the formula you used to calculate the total resistance is for resistors in parallel only. To calculate the total resistance for a combination of parallel and series resistors, you can use this formula: 1/Rt = 1/R1 + 1/R2 + ... + 1/Rn. In this case, it would be 1/Rt = 1/8 + 1/16 + 1/24. Solving for Rt, you will get 4 ohms.

To calculate the total impressed voltage, you can use the formula Vt = V1 + V2 + ... + Vn. In this case, it would be Vt = 48 + 48 + 48 = 144 volts.

To calculate the total current, you can use the formula It = Vt/Rt. In this case, it would be It = 144/4 = 36 amps.

2. For part 2.a, you can use the formula It = I1 + I2 + ... + In to calculate the total current. In this case, it would be 50 = I1 + I2. Since the resistors are in parallel, the voltage across each resistor will be the same, which is 50V. So you can use the formula I = V/R to calculate the current in each resistor. Therefore, I1 = 50/1.95 = 25.64 amps and I2 = 50/0.05 = 1000 amps.

I hope this helps! Let me know if you have any further questions.