1. You will use the OPAMP in “open-loop” configuration in this part, where input signals will be applied directly to the pins 2 and 3.
a. Apply 0 V to the inverting input. Sweep the non-inverting input (Vin) from -5 V to 5 V with 1 V steps. Take more steps around 0 V (both positive and negative). Create a table for Vin and Vout. Plot the data (Vout vs Vin). Discuss your results. What would be the ideal plot?
b. Apply 0 V to the non-inverting input. Sweep the inverting input (Vin) from -5 V to 5 V with 1 V steps. Take more steps around 0 V (both positive and negative). Create a table for Vin and Vout. Plot the data (Vout vs Vin). Discuss your results. What would be the ideal plot?
2. Create a non-inverting amplifier. (R2 = 2 kΩ, R1 = 1 kΩ). Sweep Vin from -5 V to 5 V with 1 V steps. Create a table for Vin and Vout. Plot the measured and calculated data together.
|Figure 3: Table displaying Vin vs. Vout for the non-inverting amplifier.|
3. Create an inverting amplifier. (Rf = 2 kΩ, Rin = 1 kΩ). Sweep Vin from -5 V to 5 V with 1 V steps. Create
a table for Vin and Vout. Plot the measured and calculated data together.
- For the non inverting amplifier the gain was 3. This can be seen when Vin is 1V but then Vout reaches its max at (4.27 or -3.56).
|Figure 4: Table displaying Vin vs. Vout for inverting amplifier.|
- For the inverting amplifier the gain was 2 as shown when Vin is 1V. After this, Vout reaches its max at (4.21 or -3.5).
4. Explain how an OPAMP works. How come is the gain of the OPAMP in the open loop configuration too high but inverting/non-inverting amplifier configurations provide such a small gain?
An OPAMP takes an input signal and amplifies it and can also invert the polarity of the signal if the OPAMP is set in inverting configuration. However, the output signal can not be higher than the values put into V+ and V-. When the OPAMP is in open loop configuration there are no resistors to implement a low enough gain and therefore the gain is very high and often reaches higher than V+ or V- very easily.
TEMPERATURE CONTROLLED LED SYSTEM
TEMPERATURE CONTROLLED LED SYSTEM
1. Connect your DC power supply to pin 2 and ground pin 5. Set your power supply to 0V. Switch your multimeter to measure the resistance mode; use your multimeter to measure the resistance between pin 4 and pin 1. Do the same measurement between pin 3 and pin 1. Explain your findings (EXPLAIN)
- Between pin 4 and pin 1 we measured a resistance of 2 Ohms. And the resistance between pin 3 and 1 gave us an overload because pin 3 wasn't connected to the circuit due to Vin being less than Vthreshold.
2. Now sweep your DC power supply from 0V to 8V and back to 0V. What do you observe at the multimeter (resistance measurements similar to #1)? Did you hear a clicking sound? How many times? What is the “threshold voltage values” that cause the “switching?” (EXPLAIN with a VIDEO)
Figure 5: Video explaining the circuit.
3. How does the relay work? Apply a separate DC voltage of 5 V to pin 1. Check the voltage value of pin 3 and pin 4 (each with respect to ground) while switching the relay (EXPLAIN with a VIDEO).
Figure 6: Video explaining how a relay works.
1. Connect positive end of the LED diode to the pin 3 of the relay and negative end to a 100 ohm resistor. Ground the other end of the resistor. Negative end of the diode will be the shorter wire.
2. Apply 3 V to pin 1
3. Turn LED on/off by switching the relay. Explain your results in the video. Draw the circuit schematic (VIDEO)
|Figure 7: Picture representation of the circuit.|
Figure 8: Video showing how the relay circuit works.
1. Connect the power supplies to the op-amp (+10V and 0V). Show the operation of LM 124 operational amplifier in DC mode with a non-inverting amplifier configuration. Choose any opamp in the IC. Method: Use several R1 and R2 configurations and change your input voltage (voltages between 0 and 10V) and record your output voltage. (EXPLAIN with a TABLE)
|Figure 9: Table displaying Vin vs. Vout.|
|Figure 10: Table displaying Vin vs. Vout.|