Summing and Difference Amplifier

Summing Amplifier

 In this experiment we created a simple summing amplifier with two voltages.

Pre- Lab:

First we choose a value of the resistor that greater than 1KOhms. The value for all the resistor we choose is 4.7KOhms.  

Lab:

The actual measured values for the Resistor are R1=4.63KOhms, R2=4.66KOhms and R3=4.62KOhms.

We also checked if the analog is working. First we checked wavegen channel 1(Va) and channel 2(Vb). The measured value for the first value for Va=-3.97V and Vb=0.98V. We also checked if the scope(V+ and V-) is working.

Circuit Setup:

After setting up the circuit, we test our design by measuring the values of the output voltage in different values of Va(listed below) and a constant value of Vb(1V).

Sample Vo measurement:

Using the formula Vo = - R3(Va+Vb)/R1, we can compare that values we measure and the theoretical values of Vo. Since R1=R3 we can say that Vo=-(Va+Vb). Looking at the values of Vo we can say that setup of the circuit is right.

 Difference Amplifier
 In this experiment we created a simple difference amplifier with two voltages.


Pre-Lab:
In the pre-lab we determine the relationship Va, Vb and Vo.
Vo=-2(Va-Vb)
The actual values of the resistors are also listed below. 

Lab:
We used the same setup of analog discovery as the summing amplifier. The values of of Va and Vb for part 1 and 2 are listed below, and we measured the values of Vo.

Circuit Setup:

The measured values of Vo in part 1 and 2 are acceptable since Vo=-2(Va-Vb) and Vo must be between +5V and -5V.