In the circuit when the voltage goes above 2V then at that time large current will pass through the collector of T2. And also the base current of transistor T1 goes up so that it can bring this transistor in the conduction stage. However at T1 transistor creates more and more negative. Exactly same thing occurs with the base of T2. And in turn of this T2 gradually closes and act against the starting growth of current. That how a steading effect achieved and we got a fixed value of current that will flow from LED.Rating of R in the circuit is equivalent with the LED current divided by 0.5
This circuit is based on two commonly used IC that is NE555 timer and CD4017 IC with few more components. 555 timer IC wired as an monostable oscillator. In this circuit NE555 monostable generates a clock for the circuit, which provide a oscillating wave to the output pin 3 of IC1. Monostable or one short multivibrator has only one stable state and we have to trigger it externally to return it back to its original state. CD4017 is a CMOS counter/ divider IC . It take clock signal from the clock input and turn on the 10 output in sequence, each time when it receives clock input pulses. It is the most popular IC and extremely useful in various project like Light Chaser, Matrix Die. In order to understand the working of IC one must know about its individual pin.
The project which is demonstrates a very interesting project of E-Toss. E-Toss is a very good option in place of coin toss. This project can also be used as game i.e. it can be played by two or more members and they have to choose whether a head or tale and press the switch. If the result comes out to be same what a player predict then that player won. This circuit can also be used in the games like cricket and many more where there is need to make any decision.
This multipurpose adjustable timer circuit will give you alarm after every specific interval of time. You can vary the time interval with the help of 8 way dip switch. Therefore this timer can be used in kitchen, or by students preparing for competitive exam. As many of us have habit to forget, to switch off button of gas, electric oven which lead to wastage of resources and your hard work. Now with the help of this circuit you will receive an alarm after specific time so that you can remember to off the device. Some other features of the circuit are: You can also use it as alarm to switch off the motor because while watching TV or talking over phone we forget to switch off the pump in that case also it will give an alarm. You can set the time period for coking also like we used to in microwave oven.
Main component of this circuit is IC NE555 timer.IC1 in this circuit works in astable mode. Other components that are used in this circuit are resistor, capacitor, LEDs and transistor.When power supply is on and switch pressed then voltage at pin2 and pin6 of IC1 drops. At the same duration voltage at pin3 of IC1 gets high and LED glows.For driving big quantity of LEDs (say around 50), a PNP transistor T1 (BD140) linked in the output terminal of the circuit.In this circuit we have used only 9 LEDs. We have divided the 9 LEDs in the group of three LEDs which is attached with 82 ohm resistor.
The project described below is a small model of traffic light which we daily see in our life on street. With this circuit you can control two way traffics. There will be lights on both sides, like there is red light on one side and green light will be present aautomatically on another side. It will also have yellow light to alert the passengers or drivers that now there signal are going to open.CD4017 is a 16 pin CMOS decade counter/ Divider. It take clock signal from the clock input and turn on the 10 output in sequence, each time when it receives clock input pulses.4072 is a dual 4 input OR gate. Output of OR gate goes high when any of the input goes high and if all input is low then output is also low7432 is a quad 2 input OR gate. In this also output goes high when any of the input is high and goes low when all inputs are low. 7432 contains 4 individual OR gate on single IC.
This circuit is too much pocket friendly at the same time simple to build. 555 timer, capacitor, transistors, inductor and few resistors are needed to construct the circuit.When a new call coms this circuit will provide you aoptical effect by flashing of LED. In circuit is so much useful where you are not been able to put your phone in ringing volume viz: in the offices, in your house where your infant or your any people of your family sleeping and you don’t want to disturb them or else you even don’t want to listen your phone ringtone and need some silence in your home. You can also use this circuit in the place which is full of noise and mobile ringtone and you are not been able to hear your mobile ringtones, this circuit is too much useful for you in such situation.
The doorbells produce a ringing alert sound so that the resident comes to know that there is somebody at the door. Many homes have two doors for entering. So, sometime it become confusing for the resident to find out on which door visitor is present. This project on doorbell circuit produces two different sounds and can be used simultaneously on both the doors. This circuit also gives a visual indicator so that deaf person can also know. For this we use different color LED for different door so that it becomes easy to know whether the visitor is present on front door or rear door. This simple circuit is based on transistor, diode, resistor and switches with few more components. Resistor is a two terminal passive component used to control the flow of current into the circuit.
CD4033 is a Johnson counter IC commonly used in digital display. It has a 5 stage Johnson decade counter with decoder which converts the Johnson code to a 7 segment decoded output. This means it will convert the input into numeric display which can be seen on 7 segment display or with the help of LED’s.Advantage of this IC is it can be operated at high voltage of 20V because it is highly sensitive and it can detect EMF presence in the atmosphere and it is sensitive to static charge also.When you touch the input terminal with finger, counter get’s started.Therefore care should be taken while using it. It can be used in various applications like in 7 segments decimal display circuit, in clocks, timer etc.
What is this? This is a device which will detect the organic living organisms when it is come in contact. It will send the signal in the form of electric current. If the organism is big enough, then the amount of current as a signal will found out the size of the organism. If the size of the organism is very big like an elephant then the amount of current will be very high. Oh…… this is a task to do. Let’s talk about how it actually works.How it works? I usually make very easy circuits for you so that very weak student in electric current can also be able to understand it and make it. So here it goes…..It only works with 2 transistors, both PNP and NPN. Just you should have two transistors and by connecting it in the particular pattern and then you will be ready with that.
Many times it happen when somebody comes home in night and press the door bell, We search for the porch light switch. To identify that the visitor who as press the door bell is known or unknown person before opening the door. This circuit will help you to solve the problem. When a visitor press the doorbell switch it will automatically on the porch light after sometime so that when you reach near the door you don’t have to search for light switch. This circuit will automatically off the light after some time. This circuit also has the facility to on the porch light from inside the house. In day time you can off the light with the help of switch S3. Doorbell cum light has inbuilt doorbell so you do not require to purchase a door bell.
Heat sensor senses the heat present around the sensor. When temperature rises above the set value, it will indicate the presence with the help of glowing LED. This circuit can be used in kitchen or inside your PC. If your kitchen appliances or PC are over heated, it may be possible that it will damage the expensive components present in it. So to protect them from damage we have described a simple circuit which will give an indication when temperature around the sensor increases above the level set by you. This circuit is very small and can be easily install. In short, this simple project with easy to build electronic circuit is very useful to fight with problems like overheating.The circuit is based on two IC and few more discrete components.LM35 is a precision integrated circuit temperature and its output voltage is linearly proportional to centigrade temperature.IC CA3130 is operational amplifier which combines the advantage of both CMOS and bipolar transistor on a single chip.
Everyone has studied this rule in their childhood. It stands for “bracket, “off”, “division”, “multiplication”, “addition”, “subtraction”. A mathematical operation involve a number of operators but they must carry out in a particular order. The circuit described here will help you to practically implement the BODMAS rule which we have studied.The circuit is made with the help of three IC’s namely 7404, 7408 and 4073. 7404 is a hex inverter or NOT gate IC. It is a 14 pin IC and contain 6 individual NOT gate on a single IC. 7408 is a quad 2 input AND gate IC. It contains 4 individual AND gate on a single IC. 4073 is a triple 3 input AND gate. It contains 3 individual AND gate on a single IC. LED, switches and resistors are also used in this circuit.
This simple circuit will act as a warning alarm whenever the temperature of a device exceeds above the safety level. This circuit can be used to monitor the heat built inside the devices like your PC, inverters, CD player etc. As excessive heat may affect the sensitive component and may lead to permanent damage. The main advantage of this circuit is its compactness that’s why it can be easily install in the device itself. This circuit will also give you power on indicator of a device with the help of blinking LED. Therefore it attract your attention that device is on. This circuit uses a negative temperature coefficient (NTC) as a sensor to sense the heat. This circuit can be operated on wide range of temperature vary from 5V to 12V.
The performance of each and every electronic system or electronic circuit depends upon the power supply that energizes the circuit or system. It provides required current to the circuit. Any disturbance noise in this power supply can cause problem in working or operation of circuit. If there is any deviation in this power supply level the circuit may not work properly. The accuracy and precision of circuit operation depends upon it. In some of the circuits all the calibration are done at this voltage level. So all these calibrations becomes false if there is fluctuation in supply level. There are two types of power supplies: Unregulated power supply, Regulated power supply. Unregulated supply is used in some circuits where there is no much change in required load current. The load current remains fixed or deviation is very less. Read more to know about this interesting power supply project.
Seven segment displays nowadays are commonly used in place of dot matrix display. They have found their use in places like microwave or fancy toaster oven or the same on washing machine but before using them in all these places you need to interface the 7 segment display with microcontroller or some more hardware will be required. But with the basic knowledge of 7 segments display you can use it in front of your shop or you can display your name on it. 7 segment displays numbers from 0 to 9 and some alphabets.7 segment display are labelled a to g and decimal point is usually known as DP. DP is the common point. In common cathode display they are connected to ground and rest pin are connected to supply. Similarly in common anode DP are connected to supply and rest are connected to ground. You can also use more than one display according to your requirement.
The electronics devices works in dc power supply comes with different voltage specifications. Some devices works in battery power with voltages ranging from 1.5V to 9V, but majority of the devices can be directly plugged into a power plug. Such devices have a built in AC to low voltage DC converter inside it and the voltage output of that converter will be corresponding to the design of the entire circuit. The design of a circuit actually begins with considering the value of the voltage which will be supplied to it.The circuits which work in 5V power supply are most common which contains 5V TTL devices, but there is other category of TTL devices which works in 3.3V supply. Apart from these two categories there are CMOS based circuits and there is all kind of analog circuits which are designed to work on different voltages. Those who are interested in working with all these kind of circuits should have a variable power supply source.
In this project a protoype circuit which can switch on the device when the light falls on it. For this I will use LM358 IC which is operational amplifier. I have made the circuit with LDR and few more components. But when I interchange the LDR with photodiode, phototransistor and transistor (L14F1) my circuit works well without changing any other components. Before understanding the circuit which I have developed, first let’s have a look on the components used in the circuit.LM358 consists of two independent, high gain operational amplifiers in one package. Important feature of this IC is that we do not require independent power supply for working of each comparator for wide range of power supply. LM358 can be used as transducer amplifier, DC gain block etc.
The 8-LED Flasher is built around Timer and Counter ICs. It Flashes 8 LEDs sequentially and the flashing speed can be controlled by a potentiometer. This can be used as a design pattern for decoration. But theoretically, it clears the Timer and Counter concepts in an easy way.The circuit comprises of various components like 555 Timer IC, Decade counter (CD4017), LEDs, Resistors, Capacitors, Wires & a 9V battery. The monolithic integrated circuit 555 timer can be used as square-wave generator, linear saw-tooth generator, pulse generator, time delay generator, etc. here we use it to generate square waveform i.e. it is used in the Astable Mode with a duty cycle of 66.6%.The 8 LEDs could be arranged in any pattern and thus be used as a decorative Light Toy in your living room.
There are times when it is difficult to judge the distance while reversing the car or while parking. If someone is there to help you that is great but in situations when you are driving alone then what will you do? Or you are a new driver and cannot judge the distance? This circuit will solve all these problems. You can easily install at the back side of your car. Operated at 5V power supply and can also recharge batteries. You can also use them as shadow alarm at doors to protect your car. When shadow of a intruder fall on it will also give you alarm. This alarm will provide you the musical sound that’s why it will not tease your ears. Main components of this circuit areLM358 IC, LDR, UM66 IC, speaker and few more discrete components.LM358 consist of two independent, high gain operational amplifier in one package. Important feature of this IC is we do not require independent power supply for working of each comparator for wide range of power supply.