# Understanding a schematic diagram

1. Dec 13, 2011

### knightmetal

1. The problem statement, all variables and given/known data

I'm an electrical engineering student and in this exercise I'm asked to calculate (and simulate in MicroCap or Multism) voltage gain and output resistance. The problem is that I don't understand how the voltage source (s) is/are connected according to this schematic diagram.

On the left I can see "u1" but then then I also see +10V and +5V. My teacher didn't give me a value for u1, do I need three voltage sources in this circuit or are +5V and 10+ readings I must get by setting a value for u1 based on the given data?

I'm so sorry if the answer to this is too obvious, I'm learning and honestly, I don't get it. That's why I'm here :)

Thanks a lot for your help.

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2. Dec 13, 2011

### Staff: Mentor

The +10V and +5V are for power supply connections. You'll need a source for each. The u1 is a signal source, typically a small ac signal that is to be amplified. You might want to try a 0.1V ac source to begin with and see what the circuit amplification looks like. Adjust for reasonable results.

3. Dec 13, 2011

### knightmetal

Thanks gneill,

That was my first guess but I got confused because I've always worked with one power supply, not with two as in this exercise. Plus I'm new to FET and MOSFETS so I wasn't really sure of what I was doing.

Cheers.