April 25, 2011. Op Amp I

The purpose of this lab is to practice using of Op Amp in a circuit and understand how it works. First, we receive a 741 Op Amp from the instructor. The Op Amp looks like the black little box in picture 2. Then we designed a circuit that the input voltage would be 0-1V range. and output is 10 times the input. We built a voltage divider to make the input voltage to 1V maxium. Then we connect the 1 power source to positive power supply, and another to negative power supply. Then we put resistors in the order of our design. After that, we ran out circuit, and measured the voltage of input, output, current and so on. Here is the value:

Ri	2.95k ohm		Vin	1 V
Rf	31k ohm		Vout	10.58 V
Rx	1288 ohm		Gain	10
Ry	148 ohm		Vri	0.78 V
V1	12.16 V		Iri	0.26 mA
V2	12.15 V		VRf	8.49 V

PSpice Hw

March 30, PSpice

The purpose of this lab is to find Nodal voltage, Thevenin Resistance and voltage, and Norton current by using PSpice. The difference between this time is that we are using schematics rather than capture student. The first picture shown is that we use PSpice to find nodal voltage the top two points. It clearly show the voltage to be 12V on the left, and 3.429V on the right. The second picture is showing how we practice sweep which is for helping us to do thevenin analysis. The third picture is the one we looking for. We drew a circuit on the schematics and put a current source in the place of Rload. We sweep the current from 0A to 1A of increasement of 0.1A. Then we run it, and it gave out the graph like picture 3. The thevenin voltage is when the current is 0A. Vth=20V, and the Rth is the slope of the graph which is 6Ohm. Then we replaced the current source with voltage source. After doing the same thing, we have In= 3.335A. The last graph is what we find for max power across Rload. We drew the thevenin circuit and sweep the resistance of load this time. Then we find graph of v*i and the maximum is 250micoW.