# Homework Help: Thevenin equivalanet and max power question

1. Dec 18, 2011

### takeiteasy

2. Dec 18, 2011

### cepheid

Staff Emeritus
Welcome to PF,

That website is pretty neat, although it would have been much better (for us and for your response rate) to post the problem and your steps directly here, in the forum.

Your first part is correct (it's just a voltage divider). The current through the loop on the left is I = (8 V)/(4 kΩ) = 2 mA. Then the voltage v0 across the 1k resistor is I*R = (2 mA)*(1 kΩ) = 2 V.

Your next step is wrong. The diamond-shaped thing is a voltage-controlled voltage source. Hence it is providing 240 V (NOT 240 A).

It's really unclear what the problem is asking for, but if you are trying to solve for the voltage between terminals 'a' and 'b', then just use the same technique for the right loop as for the left loop. Find the current through the loop using the given voltage and the total resistance. Then use this current to find the voltage across the 40k resistor. Be careful with signs/directions.

EDIT: I see that you have essentially done the second part correctly as well, in spite of the mistake with the units.

3. Dec 18, 2011

### takeiteasy

thank you,cepheid=) i just can't believe how i treat the voltage as current. brain explosion=)

Can you look at this mutual inductance problem and explain the sign and dot logic behind it please?

http://vyew.com/room#/844710/circuit_analysis_examples