INTRODUCTION

1.1 GENERAL INTRODUCTION

The most naturally occurring phenomena are analog in nature

analog quantities are continuous functions with time and most

transducers give analog output. With the wide rise of digital

computers there is a need to have devices that can convert from

digits to analog so that other physical quantities may also be

measured. Signals such as voltage and current are some form of

analog quantities. Digital to analog converter is basically a process

of taking a value represented in digital code such as straight binary

or BCD and converting it to a voltage to current that is

proportional to the digital value

In this mini project a 8-bit R/2R ladder network method of

conversion is implemented this means that it cannot converts

more than 8-bits of digits i.e. from 00000000 to 11111111 with the

voltage at 9v.

1.2 Aims

The aim of this mini project is to implement a digital to analogy

converter using R/2R ladder network.

1.3 Statement of the Problem

Most modern audio and video signals are stored in digital form for

example MP3 CDs and digital cameras. In order for these

devices to be heard or viewed through speakers and to display on

monitor respectively they must be converted to analog form to be

driven analogically.

1.4 Scope of the Study

The construction of this mini project solves the problem associated

with converting digital signals to analog signals. Besides as earlier

stated in the general introduction that the construction of this

project will not be more than 8-bits however the project will be

suitable for the bits between 00000000 and 11111111. The

particular bit generated depends on the particular switch that is

either Active or Inactive high or low and ON or OFF.

1.5 Methodology

There are several methods for producing a digital to analog

converter. It is not important to be familiar with all of the various

circuits schemes because digital to analog converter are available

as ICs.

The digital to analog converter using R/2R ladder is implemented

1.5.1 Power Supply

The power supply unit supplies the power to the circuit and to the

remaining units through 9v battery.

1.5.2 Digital Input

The digital inputs are generated from the pulse switch and the

R/2R ladder networks of resistor according to their position in the

binary numbers.

1.5.3 Converter

This is an operational amplifier that converts the binary scaled

current generated from the 8-bits R/2R ladder into a voltage signal

which is proportional to the digital input signals the contribution

to the output voltage from each source is considered

independently all the contribution is summed up by the

operational amplifier to yield the resulting output (Vout). This is

because the output DAC is proportional to the sum of weights

represented by these switches that are connected to the reference

voltage V Ref

1.5.4 Output

The output is a device that compares the input binary current and

to be converted voltage from the operational amplifier which is

done using a meter.