Why Is the Current Negative in This Circuit Division Equation?

[Miike012]

Can someone tell me why the current I is negative and not positive?

Im guessing the equation should be:
I = (-2)(6||3)/(6). But why the negative sign?

 

[ehild]

Well, the current has to flow in the opposite direction as indicated.

ehild

 

[Miike012]

Well, the current has to flow in the opposite direction as indicated.

ehild

Are there any general rules to follow because I'm sure most circuits won't be as obvious

 

[ehild]

There are Kirchhoff's Laws.

The 2mA current of the current source flows out of the top junction, so the same current has to flow in through the resistors. The sum of the currents flowing in is equal to the sum of the outflowing currents according to Kirchhoff's Current Law. So the current flows upward through the 2 kΩ resistor.

ehild

 

[Nickie]

The negative sign in the equation for current division indicates the direction of the current flow. In electrical circuits, current is defined as the flow of positive charge, so a negative current value means that the flow of positive charge is in the opposite direction. This is important to consider when analyzing circuits, as it affects the overall behavior of the system. In the equation you provided, the negative sign indicates that the current is flowing in the opposite direction of the conventional current flow. This could be due to the specific arrangement and components in the circuit. It is important to carefully consider the direction of current in circuit analysis to accurately predict the behavior of the system.