1. The problem statement, all variables and given/known data A device can be modeled using a current source in parallel with a resistor. This device was connected to a 5[V] voltage source, as shown in Figure P2.3a), and a current i5 of 0.93[A] resulted. The same device was then connected to a 4[A] current source as shown in Figure P2.3b), and a voltage v4 of –34[V] resulted. Find the voltage v3 if a 3[Ω] resistor, as shown in Figure P2.3c), is connected to the same device. 2. Relevant equations V = iR, KCL, KVL, Sign Conventions 3. The attempt at a solution [Freaking session expired and I lost whatever I wrote.. writing it again grrrrrr] Link to picture of diagram: http://www.mediafire.com/imageview.php?quickkey=lzuqgmqmitk&thumb=6 I define the device as the following: ----------------- [ ] [ ] Current Source Resistor [ ] [ ] ------------------ I connect this device to a 5 Volts voltage source for part a. And Apply KCL to get i2-i1 = 0.93 Amps. i2 is the current going through resistor, and i1 is the current by current source. I move on to part b, and get equations [ probably the wrong ones ], but now I can't use anything from part a because the values would be different correct? So I don't really understand how to solve this problem... Help would be appreciated! ____________________________________________________ ***Update***: Okay I understand it a bit better. For part a I use Kirchhoffs current law to find an expression for the current going through internal resistor. i2 = i1-0.93 I get an expression for Internal resistence: R = (V1 / i2) V1 is the 5 Volt power source in Part a. Going into part b. KCL law to get -i2 - i3 = 0 [ i3 is the given current source 4 Amps in part b] so i2 = -4 amps Voltage is given and current is i2. Resistence can be calculated to be 8.5 Ohms. Part c: Current Divider Rule: lets me find i2[ which will be different because Resistor was added] i2= -.396 Amps V3 ____________________________ I have another QUICK question unrelated to the above problem. If a question states that there is a device that is modeled using an ideal voltage source in series with a resistance. And that device is connected to a voltage source in the schematic. Then there will be TWO Voltage sources CORRECT? One inside the device and one that the device is connected to?