____________________________________________________

FACULTY OF TECHNICAL AND VOCATIONAL

EDDUCATION

BBV30303 ELECTRONIC 2

EXPERIMENT REPORT 3

(OP AMP CHARACTERISTIC- Offset Voltage in Amplifier with

Inverting and Non Inverting Configuration)

MEMBER GROUP

BIL NAMA MATRIK

1. Azman Bin Hanafiah DB120004

2. Muhammad Nazmy Bin Zulkifli DB120075

Check By:

Dr. Alias Bin Masek

Pensyarah Elektronik II

Submit: 02/11/2014

1.0. TITLE

OP AMP CHARACTERISTIC - Offset Voltage in Amplifier with Inverting and Non-

inverting Configuration

2.0. AIM

To improve our knowledge about operation amplifier characteristic

3.0. OBJECTIVES

3.1. To understand the Operation Amplifier (OP-AMP)

3.2. To understand the Offset Voltage in Amplifier with Inverting

3.3. To understand the Offset Voltage in Amplifier with non-inverting

4.0. EQUIPMENTS

4.1. KL-200 Linear Circuit Lab.

4.2. Experiment module: KL-23012

4.3. Instrument experiment:

4.3.1. Voltmeter

4.3.2. Oscilloscope

4.3.3. Signal generator

4.4. Basic hand tools.

4.5. Material: As indicated in the KL-23012

5.0. THEORY

An op-amp is a high gain, direct coupled differential linear amplifier choose response

characteristics are externally controlled by negative feedback from the output to input, op-amp

has very high input impedance, typically a few mega ohms and low output impedance, less than

100. Op-amps can perform mathematical operations like summation integration,

differentiation, logarithm, anti-logarithm, etc., and hence the name operational amplifier op-

amps are also used as video and audio amplifiers, oscillators and so on, in communication

electronics, in instrumentation and control, in medical electronics, etc.

5.1. INVERTING OPERATIONAL AMPLIFIER CONFIGURATION

- In this Inverting Amplifier circuit the operational amplifier is connected with feedback

to produce a closed loop operation.

- When dealing with operational amplifiers there are two very important rules to

remember about ideal inverting amplifiers, these are: No current flows into the input

terminal and that V1 always equals V2. However, in real world op-amp circuits

both of these rules are slightly broken.

- This is because the junction of the input and feedback signal ( X ) is at the same

potential as the positive ( + ) input which is at zero volts or ground then, the junction

is a Virtual Earth.

- Because of this virtual earth node the input resistance of the amplifier is equal to the

value of the input resistor, Rin and the closed loop gain of the inverting amplifier can

be set by the ratio of the two external resistors.

- We said above that there are two very important rules to remember about Inverting

Amplifiers or any operational amplifier for that matter and these are.

a. No Current Flows into the Input Terminals

b. The Differential Input Voltage is Zero as V1 = V2 = 0 (Virtual Earth)

5.2. NON - INVERTING OPERATIONAL AMPLIFIER CONFIGURATION

- In this configuration, the input voltage signal, ( Vin ) is applied directly to the non-

inverting ( + ) input terminal which means that the output gain of the amplifier

becomes Positive in value in contrast to the Inverting Amplifier circuit we saw in

the last tutorial whose output gain is negative in value.

- The result of this is that the output signal is in-phase with the input signal.

- Feedback control of the Non-inverting Operational Amplifier is achieved by applying

a small part of the output voltage signal back to the inverting (-) input terminal via a

R R2 voltage divider network, again producing negative feedback.

- This closed-loop configuration produces a non-inverting amplifier circuit with very

good stability, very high input impedance, Rin approaching infinity, as no current

flows into the positive input terminal, (ideal conditions) and a low output impedance,

Rout as shown below.

6.0. PROCEDURE

6.1. Offset voltage adjustment in the amplifier with inverting configuration

i. Insert the short-circuit clip by referring to fig 14-21 (e) and the short-circuit

clip arrangement diagram 23012-block d.5.

ii. Connected the inverting input terminal (IN3) of the OP AMP to ground.

iii. Used oscilloscope (DCV) or voltmeter (DCV) to measure the voltage in

the output terminal (OUT).

iv. View if the voltage in OUT is zero. If not, please.

a) Adjust VR2 (VR1K) to the maximum.

b) Adjust VR3 (VR100K) and view the voltage variation of OUT, so

that Vout= 0V.

Figure: 14-21 (e)

Figure: 230012-block d.5

6.2. Offset voltage adjustment in the amplifier with inverting configuration

i. Insert the short-circuit clip by referring to fig 14-21 (f) and the short-circuit

clip arrangement diagram 23012-block d.6.

ii. Connected the non-inverting input terminal (IN2) of the OP AMP to

ground.

iii. Used oscilloscope (DCV) or voltmeter (DCV) to measure the voltage in

the output terminal (OUT).

iv. View if the voltage in OUT is zero. If not, please.

a) Adjust VR2 (VR1K) to the maximum.

b) Adjust VR3 (VR100K) and view the voltage variation of OUT, so

that Vout= 0V.

Figure: 14-21 (f)

Figure: 230012-block d.6

7.0. RESULT

RESULT FOR INVERTING OP AMPLIFIER

POSITION WAVEFORM VPP FREQ

Vin

388mV

53.13Hz

Vout

420mV

52.85Hz

RESULT FOR NON- INVERTING OP AMPLIFIER

POSITION WAVEFORM VPP FREQ

Vin

396mV

53.00Hz

Vout

440mV

53.08Hz

8.0. DISCUSSION OR ANALYSIS

Some knowledge about the experiment:

i. Based on the experiment we will to know about Operation Amplifier. OP-Amp is a

three-port device having two inputs and one output. It was invented to simplify

the design of inverting and non-inverting DC amplifiers by the simple control of

external negative feedback.

ii. This deceptively simple building block is to analog electronics what nand or nor

gates are to digital electronic circuits: it reduces analog circuit design to a simple

problem of determining suitable external feedback and interconnecting networks

without the complication of having to know what's going on inside the op-amp

itself.

iii. Treating the op-amp as ideal is often all that is necessary to use it in practice,

provided we skillfully appreciate the limitations imposed by basic device

parameters that would typically include: non-infinite open-loop gain, frequency

response expressed by slew rate, single-pole roll-off frequency and its related

gain-bandwidth product GBP, non-infinite input port resistances and non-zero

output resistance; power-supply limiting or railing due to finite power supply

voltages.

iv. Although the op-amp is employed in a truly impressive array of many different

circuits, all are based in part on one or both of the following two fundamental

circuit configurations, the inverting and non-inverting DC amplifiers. You will gain

an appreciation of the power of the op-amp as a basic building block along with

some of its inherent limitations by investigation of these two basic circuits.

8.1. The Ideal Op-Amp

The ideal behavior of an op-amp implies that

a) The output resistance is zero

b) The input resistance seen between the two input terminals (called the

differential input resistance) is infinity.

c) The input resistances seen between each input terminal and the ground

(called the common mode input resistance) are infinite.

d) Op-amp has a zero voltage offset ie., for V1 = V2 = 0, output voltage VO

= 0.

e) Common mode gain AC is zero.

f) Differential mode gain, Ad is infinity.

g) Common Mode Rejection Ratio (CMRR) is infinity.

h) Bandwidth is infinite.

i) Slew rate is infinite.

- We can look the differentiation at the diagram below:

9.0. CONCLUSION

Based on the experiment we understand about the operation Amplifier in real practical,

and we got understand the Offset Voltage in Amplifier with inverting and we can

understand the offset voltage in Amplifier with Non-Inverting.

10.0. EXPERIMENT ACTICITY (PICTURE)

Figure 1: Connections for inverting OP Amplifier

Figure 1: Using Oscilloscope to measure the sine wave for input OP Amplifier

Figure 3: Using Oscilloscope to measure the sine wave for Output Inverting OP Amplifier.

Figure 4: Connections for Non Inverting OP Amplifier

Figure 2: Using Oscilloscope to measure the sine wave for Output Non Inverting OP Amplifier.

Figure 5: Using Oscilloscope to measure the sine wave for input Non Inverting OP Amplifier