Lecture
Our First Activity is to sketch the output voltage of an inverting amplifier versus time when we use time-varying voltage input.We use 9V to power our positive external power supply and grounded our negative external power supply terminal. Given that Our voltage input values are -100 mV to 100 mV:
Because this inverting amplifier with a gain of 2, our output should change between -200 mV and 200 mV, but because our amplifier only has a range of 0-9V( grounded negative power supply terminal), therefore our graph will change between 0 and 200 mV.
Our second Activity is to sketch the same graph,, change our input voltage to 0 and 200 mV:
Pre-Lab:
Our task os to design a Summing amplifier that uses input resistor greater than 1 K ohm,
In Designing our circuit we use 2- 10 K ohm Resistors as our Input resistor and another 10 K resistor as our feedback Resistor.
Next, we start measuring our input Resistor.
Below is the sketch of our circuit and measured value, with our assembled breadboard:
We then measured The V out of our breadboard with our Digital Multimeter :
Below are the values of output voltages when we set one of our input voltage to 1 and
we measured the voltage output by changing the value of V1 (inverting input) and V2(non inverting input)
Below are the graph of V input versus v Output :
our theoretical output voltage ranges between 0 and -400 mV, but because our inverting amp only has a range of 0-9 V, our output voltage will saturate to 0V the entire time.
Our third Practice is to find Output Voltage of an inverting amplifier using nodal analysis
we investigate two nodes, node A where 2 4K Resistor and 8K resistor branched and Vo, where voltage output is connected to the inverting terminal through 2 K ohm resistor. BY using nodal analysis method we calculated a potential difference of -1.6 V in output terminal.
SUMMING AMPLIFIER LAB
Pre-Lab:
Our task os to design a Summing amplifier that uses input resistor greater than 1 K ohm,
In Designing our circuit we use 2- 10 K ohm Resistors as our Input resistor and another 10 K resistor as our feedback Resistor.
Next, we start measuring our input Resistor.
Below is the sketch of our circuit and measured value, with our assembled breadboard:
We then measured The V out of our breadboard with our Digital Multimeter :
Below are the values of output voltages when we set one of our input voltage to 1 and
Our Next Activity is to drive voltage gain across a difference op Amp:
Pre Lab :
We calculated the relationship between voltage from inverting input and non inverting input and the voltage output. WE then calculated theoretical resistor needed to obtain gain of 2 from the difference opAMP. In our theoretical calculation we uses 20K ohm and 10 K Ohm resistor to obtain gain of 2 :
WE measure the actual resistance of 20 K resistor
Our difference op amp circuit :
we measured the voltage output by changing the value of V1 (inverting input) and V2(non inverting input)
Below are the graph of V input versus v Output :
Summary :
Today we learn about 5 Type of OP AMP: unity gain OP AMP, Inverting OP AMP, non-inverting OP AMP, Summing OP AMP, Difference OP AMP. Unity gain Amplifier gives a gain of one and works to isolate two sides of the circuit. To Obtain Unity gain buffer, we shorted (Rf=0) the output voltage with inverting input. Inverting amp, amplify input voltage and change the polarity of the input voltage. To obtain inverting amplifier we connected the input voltage to inverting terminal and ground the non-inverting terminal.
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