# Electrical Engineering - Parallel Circuits - Discussion

Discussion Forum : Parallel Circuits - General Questions (Q.No. 2)

2.

The total resistance of a parallel circuit is 50 . If the total current is 120 mA, the current through the 270 resistor that makes up part of the parallel circuit is approximately

Discussion:

16 comments Page 1 of 2.
Anu said:
2 weeks ago

As the resistances are in parallel so,

Req = R1 * R2/(R1+R2).

So from here, 50 = 270 * R2/(270+R2).

R2=61.3ohm.

Now, using the current division rule for I, we get;

I2 = I * (R2/R2+R1).

I2 = 22ma.

Req = R1 * R2/(R1+R2).

So from here, 50 = 270 * R2/(270+R2).

R2=61.3ohm.

Now, using the current division rule for I, we get;

I2 = I * (R2/R2+R1).

I2 = 22ma.

Raguram said:
2 years ago

Whatever may be a count of the resistance in parallel.

That's not important here ...

here, they were given total resistance and total voltage and all the resistance is connected in parallel.

Let's make it simple..voltage across each resistance is the same (because of the parallel circuit)

Total voltage = voltage drop in anyone of the resistance part.

Total current * Total resistance = Individual current* particular resistance value,

50 *120 = x *270.

X = (50 *120)/270.

X ~ 22mA.

That's not important here ...

here, they were given total resistance and total voltage and all the resistance is connected in parallel.

Let's make it simple..voltage across each resistance is the same (because of the parallel circuit)

Total voltage = voltage drop in anyone of the resistance part.

Total current * Total resistance = Individual current* particular resistance value,

50 *120 = x *270.

X = (50 *120)/270.

X ~ 22mA.

(4)

Azeem said:
7 years ago

Voltage division For Series Circuits.

Vr = (R/Req) * V.

Current Division for parallel circuit

Ir = (Req/R) * I.

Where Req is the equivalent resistance (either series or parallel.

R is the resistance for which you want to determine the voltage or current.

Ir and Vr are the current and voltage respectively of the resistor in question.

I and V are the current and voltage respectively to be divided.

Vr = (R/Req) * V.

Current Division for parallel circuit

Ir = (Req/R) * I.

Where Req is the equivalent resistance (either series or parallel.

R is the resistance for which you want to determine the voltage or current.

Ir and Vr are the current and voltage respectively of the resistor in question.

I and V are the current and voltage respectively to be divided.

Puja said:
7 years ago

I can't understand. Someone explain me clearly.

(2)

Sindhu said:
9 years ago

@Abd.

This method can be used as you have the total resistance as 50 ohm and total current as 120 mA given.

This method can be used as you have the total resistance as 50 ohm and total current as 120 mA given.

ABD said:
9 years ago

I think we can do by ohm's also. In first case we know resistance value and current by this we can find voltage value. In second case we we know resistance value and we already find voltage in first case by using these we can find current.

Ex : Case 1:

V = IR.

V = 50*120 ma.

V = 6 volt.

Case 2:

I = v/r.

I = 6/270.

I = 22 ma.

Let me know this method is correct or not.

Ex : Case 1:

V = IR.

V = 50*120 ma.

V = 6 volt.

Case 2:

I = v/r.

I = 6/270.

I = 22 ma.

Let me know this method is correct or not.

(1)

Shiva said:
10 years ago

R1 = 50 ohm.

I1 = 120 mA.

V = I*R(50*120 = 6000 mV).

I2 = V/R2 = 6000/270

= 22.22 mA.

I1 = 120 mA.

V = I*R(50*120 = 6000 mV).

I2 = V/R2 = 6000/270

= 22.22 mA.

(3)

Mrakovic said:
1 decade ago

Ri = 50ohm.

Ii = 120 mA = 0.120A.

R1 = 270 ohm.

U = Ii*Ri = 0.120*50 = 6V.

I1 = U/R1 = 6/270 = 0.022A = 22 mA.

Ii = 120 mA = 0.120A.

R1 = 270 ohm.

U = Ii*Ri = 0.120*50 = 6V.

I1 = U/R1 = 6/270 = 0.022A = 22 mA.

MOHIT RAJHANS said:
1 decade ago

R1 and R2 are in parallel,

So (R1) * (R2) / (R1+R2) =50.

R1 = 270 ohm, R2 is unknown.

We get R2 = 61. 3 ohms.

Now using current division rule we get,

I2 = (Total current) * (R2/R1+R2).

= 120* (61/331).

= 22 mA.

That is the required answer, hope you people understand.

So (R1) * (R2) / (R1+R2) =50.

R1 = 270 ohm, R2 is unknown.

We get R2 = 61. 3 ohms.

Now using current division rule we get,

I2 = (Total current) * (R2/R1+R2).

= 120* (61/331).

= 22 mA.

That is the required answer, hope you people understand.

Sarkars said:
1 decade ago

Concept of raja and ramesh wrong, Sehegal is correct.

Try this way:

Total voltage = 50ohm * 120mA = 6 V

Current through 270 ohm resistor = 6 V/270 ohm = 22 mA

Try this way:

Total voltage = 50ohm * 120mA = 6 V

Current through 270 ohm resistor = 6 V/270 ohm = 22 mA

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