8/11/2019 Proj3_Final_KMW_F05

1/17

Simple Amplifier Circuit

Beth Keswani, Les Murphy,

and Steve Wilt

8/11/2019 Proj3_Final_KMW_F05

2/17

What is an amplifier?

An amplifier is an

electronic device that

enlarges or extends

power, current, or

voltage. We are using

the amplifier for sound.

8/11/2019 Proj3_Final_KMW_F05

3/17

Amplifiers In Action

Audio amplifiers are

used in stereo systems,

car systems, and

personal radios. Bands

also use amplifiers to

create a louder sound.

I have an

amp in me!

Whoa!

Thats

loud!!!

This is Les

8/11/2019 Proj3_Final_KMW_F05

4/17

What Do We Need?

Op Amp- LM386

Variable Resistor- 102

Capacitors- 10F and 250F

Voltage Input- 1KHz

Low Impedence Resistor- 4,

8, 16, 32

Wave generator for

voltage input

Op amp

Variable

Resistor

Capacitors

Resistors

8/11/2019 Proj3_Final_KMW_F05

5/17

Basic Schematic Drawing

8/11/2019 Proj3_Final_KMW_F05

6/17

PSpice Schematic Model

8/11/2019 Proj3_Final_KMW_F05

7/17

Whoo Hoo! It worked!

8/11/2019 Proj3_Final_KMW_F05

8/17

How to Read the Results

The yellow wave is the output.

The blue wave is the input. We can tell this worked because there is a

gain, so it shows that the amplitude wasincreased.

To calculate the gain, we usedchannel 1 (yellow wave) peak to peak

channel 2 (blue wave) peak to peak.

8/11/2019 Proj3_Final_KMW_F05

9/17

The Tektronic Results Are In

This is using a 4

resistor.

The gain is 154.

8/11/2019 Proj3_Final_KMW_F05

10/17

More Fun Graphs

This is using the 8

resistor.

The gain is 205.

8/11/2019 Proj3_Final_KMW_F05

11/17

Keep The Fun Coming

This is using the 16

resistor.

The gain is 170.

8/11/2019 Proj3_Final_KMW_F05

12/17

Awthe fun is almost over

This is using the 32

resistor.

The gain is 189.

8/11/2019 Proj3_Final_KMW_F05

13/17

PSpice and Tektronic Team Up!

These results will show the PSpice results

and the Tektronic results compared together.Each PSpice result includes a graph similar

to the Tektronic results and also a graph

showing the frequency.

8/11/2019 Proj3_Final_KMW_F05

14/17

Using the 4resistor

Time

0s 1.0ms 2.0ms 3.0ms

V(R2:2) V(V1:+)

-200mV

0V

200mV

Frequency

100Hz 10KHz10Hz

V(R2:2) V(V3:+)

0V

5V

10V

Exp. 1Results

Measured Value Calculated Value

Gain 154 100

Percent Error is 54%

8/11/2019 Proj3_Final_KMW_F05

15/17

Using the 8resistor

Frequency

100Hz 10KHz10Hz

V(R2:2) V(V3:+)

0V

5V

10V

Time

0s 1.0ms 2.0ms 3.0ms

V(R2:2) V(V1:+)

-400mV

0V

400mV

Exp. 2Results Measured Value Calculated Value

Gain 205 200

Percent Error is 2.5%

8/11/2019 Proj3_Final_KMW_F05

16/17

8/11/2019 Proj3_Final_KMW_F05

17/17

Using the 32resistor

Frequency

100Hz 10KHz10Hz

V(R2:2) V(V3:+)

0V

5V

10V

Time

0s 1.0ms 2.0ms 3.0ms

V(R2:2) V(V1:+)

-2.0V

0V

2.0V

Exp. 4Results Measured Value Calculated Value

Gain 189 225

Percent Error is 16%