555 Timer

The 555 timer is used as a timer, pulse generator and oscillator, etc. The 555 timer has 3 

modes, namely, monostable, astable and bistable modes. Each have different usage and effects 

on the 555 timer. Here in this example, we will use the 555 timer in astable mode making use 

of it as an oscillator.

Here is a given pin layout of the 555 Timer:

This also has a standard circuit as shown below:

The resistances can be assumed. After having an assumed value for the resistors, the value 


for the capacitance can be computed using the given formula:

where:

Ø  f = frequency of the oscillation

Ø  C = is the capacitance in Farad

Ø  R = Resistance in ohms

Using the computed and assumed values, we can now construct a 555 timer circuit. To 


realize the resulting oscillation, we will connect a LED to the output. This will make the LED 


blink slowly or fast depending on frequency of the oscillation. Higher frequencies will tend to 


make the LED blink at a very fast rate that it will appear as though it did not turn off at all.

As for our final output, here is what we have:

Magnitude Comparator

The Magnitude Comparator is a type of device which compares the two 4 bit binary inputs and determines the output which are the greater than, the equal, and the less than. This device states A>B, A=B, and A<B.

To obtain this experiment, here is a schematic diagram of the experiment.

 And here is the final output of our work:

FULL SUBTRACTOR

 A Subtractor is a Logic that allows the subtracting of binary coded numbers. In this activity we were able to subtract binary coded numbers using the /XOR/ gates, and LED indicators.

Before assembling the circuit we need to know where the IC should be connected, therefore we first need to create the truth table and create a circuit diagram based on the results of the truth table.

After completing the first and second process we need to determine the logic gates diagram of the IC being used in the circuit, and then we simply assemble the circuit by implementing the output based on the circuit diagram and connect the wires to their designated input and output points of every element in the circuit.

Here is the schematic diagram for a 1-bit binary full subtractor:

Now, for our truth table, we obtain this:

Just like our Full Adder, we will have the same 4-bit full subtractor combination:

As for the result, we have this for our final output:

FULL ADDER

In this activity, we will create a full adder which consists of a 4 bit binary number. 


Here is a schematic diagram for a 1-bit binary full-adder.

Now we generate our truth table:

 Afterwards, we will create a diagram for a 4bit full adder combination:

Since we have our full adder combination, we will construct this n our breadboard to obtain our full adder experiment just as seen from the pictures below:

The Seven Segment Display

A Seven Segment Display (SSD) is a form of electronic display device for displaying decimal numerals. This is widely used in digital clocks, electronic meters, and other electronic devices. In this activity, we will show how we were able to display decimal numerals (0-9) using binary coded decimal via the SSD.

Before proceeding on, be sure to have an idea how an SSD work and most importantly its pin configuration. Below is an image showing the pin configuration of the SSD. SSD has two types of common. The Cathode and the Anode. The cathode is a common ground while an anode is a common vcc. As for this experiment, we used a cathode, because its common is ground and all our inputs are positive, since an IC produces an output of a positive value. As you can see on the image, there are 7 inputs for this component device. By analyzing this component, we can use a 4bit binary code (A,B,C, and D).

Now that we have our 4bit binary code and our 7 inputs for the display, we can create our truth table. Here is an image of the truth table showing an output of numerical values from 0-9.

Now, we can proceed to our K-Map:

After having our K-Map, we can convert our equation into a schematic diagram:

Finally, here is the final output after implementing our schematic diagram into the breadboard:

Water Level Indicator System

A water tank system is in need of a level indicator which determines 9 water levels. Ten lamps are used to provide visual indication of the water levels. This is called a water level indicator system which provides the following lamp outputs:

Level 1 - L1 and L2

Level 2 - L2 and L3

Level 3 - L3 and L4

Level 4 - L4 and L5

Level 5 - L5 and L6

Level 6 - L6 and L7

Level 7 - L7 and L8

Level 8 - L8 and L9

Level 9 - L9 and 10

And when there is no water, all lamps will light up.

Before proceeding in constructing the circuit, let us first analyze the problem statement with the use of the truth table. Therefore, it would be easy enough to break down the equation step by  step. This is the reult from the truth table: 

After producing our truth table, we are now able to accede our k-map. This is where our K-map will be applied. 

Note: If you would like not to have an output with the remaining conditions which are not present on the truth table, convert all the asteries into 0 in order to have a 0 output during the application of the rest of the truth table.

Since we have obtained our equations, we are ready to draw our schematic diagram:

And here is our final output:

Flow Rate Sensing Device

This flow rate sensing device is used on a liquid transport pipeline function. This device provides a 5 bit- output in which all the 5-bit becomes 0 of the flow rate is less than 10 gal/min. The first bit is 1 if the flow rate is at least 10 gal/min. The first and second bit is 1 if the flow rate is 20 gal/min. the first, second and third bit is 1 if the flow rate is at least 30 gal/min and so on. The five bit is represented by A,B,C,D, and E are used as inputs to the device that provides two outputs which is Y and Z. The output Y is 1 if the flow rate is less than 30 gal/min. and the output Z is 1 if the flow rate is at least 20 gal/min but less than 50gal/min.

First we Analyze the problem statement given and formulate a Boolean Equation for the system. Then we simplify the equation in any method in which we are comfortable with. The simplified equation would serve as our schematic diagram for the construction of the system.

Simplification:

Y= A’B’C’D’E’ + AB’C’D’E’ + ABC’D’E’

  = B’C’D’E’(A+A’) + ABC’D’E’

  = C’D’E’(AB+B’)

  = C’D’E’[(A+B’)(B+B’)]

  = C’D’E’(A+B’)

Y= AC’D’E’ + B’C’D’E’

Z= ABC’D’E’ + ABCD’E’ + ABCDE’

  = ABD’E’(C’+C) + ABCDE’

  = ABD’E’ + ABCDE’

  = ABE’(D’+CD)

  = ABE’[(D+C)(D’+D)]

  = ABE’(D’+C) type

Z= ABD’E’ + ABCE’

After obtaining our simplified equation, we can proceed to our truth table:

Now that we have our truth table, we are able to draw our schematic diagram:

And here is the Final Output(as observed in the picture, there are additional 5 LED that are placed. Those 5 LED are actually the indicators for the gal/min (10,20,30,etc). It is not necessary to add them in the circuit, but it is much more comprehensive and reasonable if they were placed in order for you to determine if the led is synchronized with the truth table and if they are functioning as well.)