Electrical Engineering - Parallel Circuits - Discussion

Discussion Forum : Parallel Circuits - General Questions (Q.No. 17)
17.
A sudden increase in the total current into a parallel circuit may indicate
a drop in source voltage
an open resistor
an increase in source voltage
either a drop in source voltage or an open resistor
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
18 comments Page 1 of 2.

Saurabh K. Chhaya said:   1 decade ago
I says answer is only 'c' because if source voltage incresed at that time current will incresed or when resistance decreases current increases so how it is possible if resister open in parallel circuit so total resistance indreses not decreses.

Kalyan patnaik said:   1 decade ago
The option won't be D or B, because in parallel circuits the equivalent resistance will increases when a resistor opens from the parallel branch. And hence current decreases but not increases.

Chintan said:   1 decade ago
As mentioned that this is PARALLEL CIRCUIT, Current can increase only in two conditions:

1) Either resistance decreases (In this case total resistance can be decreased only if another resistor is added in parallel).

Or

2) Voltage, applied to the circuit, increases.

So answer should be [C].

I agree with Saurabh.

Shraddha said:   1 decade ago
Given that it is a parallel circuit Current will suddenly increase when there is open circuit (because open circuit Means infinite resistance, and current always follows low resistance path).

But I don't get the concept of drop in source voltage because voltage in parallel circuit Is constant.

Viper said:   1 decade ago
Whenever you'll open the resistor to accommodate for the value of current which was flowing through the current will get redistributed in all branches with an increased value.

Jay tiwari said:   1 decade ago
Yes answer is c, not d because we calculate with assume value like:

V = 10.
I1 = 5 amp.
I2 = 2 amp.
I3 = 1 amp.

Then resister value is fallowing:

R1 = 2 ohm.
R2 = 5 ohm.
R3 = 10 ohm.

If resistance are constant we do not increase current without increasing in voltage.

You can check it with put the value an calculation.

Chetan Krishna said:   1 decade ago
I = V/R;

So I can increase if either source voltage increases or if the effective resistance decreases. But the effective resistance increases if one of the resistors is open.

So 'B' & 'D' are wrong. The voltage has to increase if current has to increase so the correct option is 'C'.

VAGEESH said:   1 decade ago
Here open circuit indicates infinite resistance. So in parallel circuits total resistance is 1/R i.e 1/ (infinity) i.e ZERO.

Thus current I=V/R i.e V/0 i.e infinite current flows when there is a open circuit in case of parallel connection. But current also increases as source voltage increases since I is proportional to V.

Chethan said:   1 decade ago
Answer : C

In parallel circuit if any branch resistor is removed the equivalent resistance increases, current reduces (current is inversely proportional to resistance), as current is directly proportional to applied voltage so if applied voltage increased the circuit current increases.

Adesh said:   1 decade ago
Opening a resistance in a parallel circuit will decrease total current. So answer is C only.


Post your comments here:

Your comments will be displayed after verification.