INTRODUCTION

OBJECTIVE
The objectives from the ADC experiment by using ADC0804 are
i. To learn the output from the ADC0804 that light up the LEDs is actually on how
the digital value can be 0 or 1.
ii. To understand what is actually the bits in analog
iii. To compare the result of analog and digital by using theoretical and
experimental.
iv. To analyse the error happen between the theoretical and experimental.
v. To understand the theoretical calculation on how to determine whether the
binary is zero or one.
LIST OF COMPONENT
All the components below were being used in conducting the experiment based on the lab
sheet.

No Components Quantity
1 ADC0804 1
2 Breadboard 1
3 Resistor 2.5 KΩ 2
4 Resistor 10 KΩ 1
5 Capacitor 150p 1
6 LEDs 8
7 Digital multimeter 1
8 DC power supply 1
9 Aligator clip cable 2
10 Wires 12

METHODOLOGY

For this experiment, the important component was ADC0804 that able to convert digital analog
input into digital input that being showed by the LEDs. Below is a diagram that showed the pin of
ADC0804 component.
Pin no Pin name Function
1 Chip select, cs To activate the ADC in low condition
2 Read, RD As an input pin where the data from high to low will be
registered as output pin to convert it
3 Write, wr Low to high pulse will be given at input pin for conversion
4 Clock in, Clk in As an external clock at clock input pin.
5 Interupt,INTR When conversion is complete the pulse goes low
6 Vin (+) Function as analog non inverting input
7 Vin(-) Function as inverting input
8 Analog ground, A 0V
GND
9 Vref2 Function to set analog input as reference voltage.
10 Digital ground 0V
11 Data Bit The digital output for the pin
12 Data Bit The digital output for the pin
13 Data Bit The digital output for the pin
14 Data Bit The digital output for the pin
15 Data Bit The digital output for the pin
16 Data Bit The digital output for the pin
17 Data Bit The digital output for the pin
18 Data Bit The digital output for the pin
19 Clock R The clock pin functioned as the internal clock source is
used.
20 VCC Voltage being supplied with 5 volt
ADC circurt setup
From the labsheet, the circuirt must be followed as below as the connection must be correct
and proper to prevent any failures happen. The 470 Ohm of resistor can be ignored and all
the data bit pin can be direct connect to the LEDs.

As the experiment had been carried out, the connection of the circuit on the board will be as the
figure below.
From the experiment, all the components listed had been pinned on the board. When
power supply supplied to the pin 20 (VCC) with 5 volts, the power supplied became a
voltage reference. The potentiometer will adjust the certain value of voltage to be in the
circuit so it will allow the value and make the some of the LEDs light up based on the voltage
being adjusted. The total eight LEDs will Onn or off based on the voltage that can be seen in
the result.

RESULT AND DISCUSSION

Lab 3- Nyquist frequency

Input Calculated Measured Measured Different Error (%)

voltage (V) digital value digital value digital value calculated
(LED) (V) and
measured
value
0 00000000 00000000 0
0.5 00010101 00001110 0.2734
1.0 00101010 00101100 0.8594
1.5 01001010 01010000 1.5625
2.0 01010101 01101000 2.0313
2.5 01010101 10000101 2.5977
3.0 10010000 10100111 3.2617
 3.5 10101000 11011111 4.3550
4.0 11001000 11101111 4.6680
4.5 11100000 11111111 5
5.0 11111111 11111111 5

Calculation of digital value

Table below show the calculation of the voltage depending on the bits. The calculation can
5
be performed by using the formula V =
2𝑛

Bits Voltage (V)

7 5
= 2.50000
21
6 5
= 1.25000
22
5 5
= 0.62500
23
4 5
= 0.31250
24
3 5
= 1.56250
25
2 5
= 0.078125
26
1 5
= 0.039063
27
0 5
= 0.0195312
28

Based on the calculation of the voltage, those values are needed to perform a manual calculation of
converting analog to digital. To determine the binary whether it can be one or zero, comparison of
the value of V that being calculated must be compare to Vin. Vin is a value of the voltage enter to
the circuirt had been control by the potentio meter.

Condition 1: If Vin > V, MSB = 1 (ON) Condition 2: If Vin < V, MSB = 0 (OFF)

Based on the condition above, the On or Off reflecting to the LEDs whether it light up or not. Every
bits with given Vin and Vref can perfume a calculation to determine whether the binary is 1 0r zero.
Calculation Analog value.