circuit analysiscurrent-sourceresistors
I have the following circuit:
I am a beginner at this stuff, so… 😉
Ok, the question is to calculate the voltage across the terminals A and B? I have no clue how to do that? You can't just take together some of the resistors. The Node method seems a little overkill (only based on the small amount of elements).
Question: What is the voltage across the terminals A and B?
P.S. The weird box (for some) in the top is a current source.
From what you said I guess that the schematic is this:
simulate this circuit – Schematic created using CircuitLab
The resistors are in series, so you need to calculate the power using the correct voltage. The voltage \$V\$ is the voltage across both resistors and in the schematic is called \$Vac\$.
You need to remember that \$V = Vac = Vab + Vbc\$.
In order to calculate the power dissipated by R1 you need to use \$Vab\$, that is the voltage across R1.
You're trying to find the Thevenin equivalent voltage of the network.
This is the voltage that the network produces when the output is open.
When the output is open, no current flows out or in to the a terminal.
Therefore no current flows through the 1 ohm resistor.
Since no current is flowing through the 1 ohm resistor, the voltage across it is 0, by Ohm's law.
Best Answer
First of all, lets re-arrange the components to see what's actually happening. As you can see, you have a simple voltage divider:
simulate this circuit – Schematic created using CircuitLab
To get the voltage across A and B, use Ohm's Law: $$ V = I*R $$ To find the total R, you first need to find the parallel value of R1 and R2: $$ R_p = {R1*R2\over R1+R2} $$ and then $$ R_t = R_p + R3 $$