Electronics Mini projectsAjay Di sharma
CircuitsToday is listing some free engineering mini projects that can be presented and designed by students for their exams. These mini projects are applicable for B-Tech/BE engineering students from various streams like Electronics and Instrumentation (EI), Electronics and Communication (ECE), Electrical Engineering (EEE), diploma and so on. Though the electronic circuits may look complex, they are explained in detail along with a circuit diagram, and are explained with links of all devices that are used in the circuit. Please note that these projects are meant for students, hobbyists and enthusiasts. If there are any doubts regarding the circuit, feel free to comment on the post. You can also bring in any modifications you want, and ask us if you have doubts. Furthermore, please go through the existing comments to get a better idea of the electronics mini project topics.
1. Street Light Circuit
This minor mini project is used to design a street light that brightens up when night falls and automatically turns OFF when day light comes in. In order to detect the amount of light that is needed to decide when to cut-off the circuit and later activate it is done with the help of a sensor called Light Dependent Resistor (LDR). The main principle used behind the LDR is that, the presence of light causes the resistance of the sensor to go low. You can modify he circuit by placing LED’s instead of the 230 volt lamp. To know more about it, check out the comments given in the circuit. The circuit is comparatively easy to design, and further modifications can be made according to your choice.
2. Battery Charger Circuit Using SCR
This is one of the most basic and best mini projects in electronics. A Silicon Controlled Rectifier (SCR) is used to rectify the AC mains voltage to charge the battery. The circuit consists of basic transistor switching methods and the components are cheap and are available in all electronics shops. A detailed description about the post is also given, which will give you a better idea.
3. Air Flow Detector Circuit
This simple mini project is used to design an indicator to show the rate of air flow in a given space. The air flow is sensed with the help of an incandescent bulb filament. The variations due to the change of resistance in the bulb due to the air flow are given to the input of an LM339 operational amplifier. The circuit diagram and a better description of the circuit is given in the post above. Further modifications can be brought to the circuit and some of them are given in the comments section.
4. Water Level Alarm Circuit
This circuit is used to produce an alarm output (bell or light), when the level of water rises above a certain level. This circuit uses a basic astable multivibrator made from a 555 timer IC. A resistance probe is set on a point at which the alarm is to set ON, as soon as the water rises up to that level. A detailed circuit can be seen in the post above. The number of components needed for this circuit is very less and can be easily assembled on a PCB.
5. Low Cost Fire Alarm Circuit
This circuit can be used for detecting a fire and producing an alarm, thus alerting the people in the building where it is installed. A transistor sensor called BC177 is used to sense the heat produced due to the fire. A preset level can be kept for the transistor. As soon as the temperature rises above the set preset level, the leakage current of the transistor rises, thus driving the other transistors in the circuit. A relay is also used to switch the bell load as its output. The components needed for the circuit can be obtained easily and the circuit is easy to design.