{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

lab 8 2010 op amp - pressure transducer

# lab 8 2010 op amp - pressure transducer - L AB 8 O...

This preview shows pages 1–3. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: L AB 8: O PERATIONAL A MPLIFIER C IRCUITS- E LECTRONIC M ANOMETER I Objective and background: The goal of this laboratory is to help you review basic operational amplifier circuits where the op- amp is used “open-loop” (no feedback resistor) or “closed-loop” (with a feedback resistor). The objectives of the laboratory are: 1. To measure the saturation voltages of a 741 op-amp; 2. To analyze, build and demonstrate the function of a positive level dectector; 3. To analyze, build and test a noninverting op-amp amplifier and an inverting op-amp amplifier; 4. To diagnose certain faults in op-amp amplifier circuits 5. To combine a single op-amp differential amplifier and a pressure transducer to build a simple electronic manometer. A 741 operational amplifier chip and the op-amp symbol are represented on the following graph. The op- amp is a high-gain differential amplifier with two inputs: the noninverting input Vin+ (pin 3) and the inverting input Vin- (pin 2). The op-amp has one output Vout (pin 6). In open loop circuits, the output voltage Vout is related to the difference (Vin+ - Vin-): Vout = A (Vin + - Vin-) ol The open-loop gain A ol is very large: 100,000 or more. Therefore the slightest difference between the two input voltages brings the op-amp into saturation. The output voltage is one of the saturation voltages (+V sat ) or (-V sat ). The saturation voltages are related to the supply voltages V CC and -V CC at pins 7 and 4: +Vsat V- 2 volts-Vsat - V + 2 volts CC CC ≈ ≈ 4-Vcc V in+ 3 5 6 V in- 2 1 7 8 V in+ Vou t-Vcc V in- +Vc c +Vc c Vou t Many useful op-amp amplifiers circuits use negative feedback materialized by a resistor between the output of the operational amplifier and the inverting input. Circuits with negative feedback have a closed- loop gain that does not depend on the open-loop gain. The closed-loop gain is function of external resistors 1 attached to the op-amp pins. Op-amp circuits with negative feedback are analyzed using the following rules: 1. The voltages at the input pins are equal: Vin+ = Vin-; 2. The inputs do not draw or source any current: I in + = I in- = 0. II Saturation voltages: Prelab: Consider a 741 op-amp used "open-loop" and powered with a +15/-15 V split supply. V in+ V in- Vou t +15 V-15 V Use the information provided in the "background" section to predict the output voltage Vout for the following conditions (if the output cannot be predicted, enter a ?): Vin+ 0.1 V 1 V-1 V 0 V 0 V 0 V 1 V 0.3 V-5 V Vin- 0 V 0 V 0 V 1 V- 1 V 0 V 1 V 0.4 V-2 V Vout 13 13-13-13 13 ? ?-13-13 Procedures: a) Connect a 741 op-amp as shown on the following diagram. b) Set up the input voltage conditions listed in table 1 below by selecting the proper power source for the potentiometers and adjusting the wiper positions; Use the scope to read the two input voltages and the DMM to read the output voltage Vout for the following conditions. Compare with the predictions from the prelab....
View Full Document

{[ snackBarMessage ]}

### Page1 / 9

lab 8 2010 op amp - pressure transducer - L AB 8 O...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online