Category: Electronics Projects

Sound Operated Light and Alarm Circuit

Engineeering Projects
circuit diagram of sound operated light and alarm

Various types of security-based projects are already available on bestengineeringprojects.com. Now here is sound operated light and alarm that is used as an intruder alarm, activated when any sound is detected (like the opening of doors, knocking, or door opening) and starts flashing with a sound that alerts you of an intruder. After the second sound pulse is turned off. Circuit Description of Sound Operated Light and Alarm The circuit of sound-operated light and alarm is designed using a pair of timer IC (NE555), a dual JK flip flop IC…

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LED Running Light Circuit

Engineeering Projects

Various types of running or disco lights are already available on bestengineeringprojects.com. Now here very simple LED Running light circuit using two transistors. Circuit Description of LED Running Light Circuit: The entire circuit of LED running light is designed using two general purpose NPN transistors. The design and working of this circuit are very simple and straightforward. Both of these transistors are configured in astable multivibrator mode. Initially when no power supply is connected, both the transistor drives to cut off region and none of this LED glow. But when…

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Nocturnal Screamer Circuit using CD4099

Engineeering Projects
circuit diagram of nocturnal screamer

Here is simple electronic fun project which is designed using digital gate IC (CD4092BE) called Nocturnal Screamer Circuit using CD4099. In absence of light it produce loud scramming sound but when light is switched on, sound will disappeared. In this way we can used this project for fun. Circuit Description of Nocturnal Screamer Circuit using CD4099 The circuit of nocturnal screamer is designed using quad two input NAND gate IC (CD4099BE) is shown in figure 1. Here LDR is used as sensor which detects light and change its internal resistance…

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Ni-Cd Battery Charger

Engineeering Projects
circuit diagram of ni-cd battery charger

These days many of electrical appliances (watch, RC car, radio etc) use Ni-Cd battery. Here is a simple circuit of Ni-Cd battery charger in the series of easy electronics projects. Circuit Description and working principle of  Ni-Cd Battery Charger Basically Circuit of Ni-Cd battery charger is rectifier. The input from AC mains is directly given to the circuit through resistors R1 and R2, where resistor R1 is used to limit the surge current and resistor R2 with capacitor C1 is used to limit the leakage charge current. The output from…

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Aural Metronome Circuit

Engineeering Projects
aural metronome circuit diagram

A metronome is a device which produces regular beats and is measured in beats per minute. Here is project called aural metronome circuit which produce fixed sound (Tick – Tick) like quartz watch. The stability of pulse can be adjusted from 40 to 400 ticks per minutes using preset VR1. Circuit Diagram of Aural Metronome Circuit The circuit of aural metronome is designed using a CMOS quad NAND gate IC (CD4011), out of which we uses two NAND gates only. Variable resistor VR1 is used to control the rate of…

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Mini Laser Turret

Engineeering Projects
circuit diagram of mini laser turret

Here is a fun project to set up a model battlefield using some components. The project mini laser turret can amidst the miniature battlefield. Circuit Description of Mini Laser Turret: The circuit of mini laser turret is designed around dual timer IC (NE556) and two servo motors. IC NE556 is a combination two timer IC (NE555), which is used to generate the pulse for drive servomotor. Each timer IC is used in astable mode whose frequency or period is depends upon RC components connected to it. It’s high period can…

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Laser Voice Transmitter Circuit

Engineeering Projects
author prototype of transmitter unit

The engineer like to communicate with their mates but radio wave is too easy to intercept using light with morse code is tricky. Here Laser Voice Transmitter Circuit uses a laser beam to transmit the voice. Circuit Description of Laser Voice Transmitter Circuit:- Most all communication systems comprised of two parts, the project laser voice transmitter also comprised of two parts i.e. the transmitter circuit and the receiver circuit. The transmitter circuit:- The transmitter circuit is built using a microphone, audio amplifier, laser diode, and a few passive components. A…

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Voice Recording and Play Back Circuit using APR9600

Engineeering Projects
Circuit diagram of Recording and playback with auto rewind option

There are various types of voice processing chip (IC) with various features for speech compression and processing is readily available. Here is projects called Voice recording and play back using chip (APR9600). An APR9600 is a single chip voice recorder and playback device from Aplus integrated circuits. This chip used flash non volatile memory to store up to 256 voltage levels. i.e. for 32 to 60 seconds. This chip have many features like, one can select sample rates with consequent quality and recording times. Microphone amplifier, automatic gain control (AGC)…

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Mosquito Repeller Circuit

Engineeering Projects
circuit diagram of mosquito repeller

Here is a simple circuit called mosquito repeller in the series of easy electronic project. The circuit of mosquito repeller uses few passive components. Circuit Description and Working Principle of Mosquito Repeller Circuit: The circuit of mosquito repeller is so simple that any-one can understand. The input of 220 volt AC from mains is directly given to the circuit; two resistors are connected in parallel as current divider circuit. Neon lamp is used as indicator to check whether the circuit works properly or not. An aluminum plate is connected to…

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Disco Light Circuit

Engineeering Projects
circuit diagram of disco light

Blinking and shimmering of lights in disco keep everyone amazed, the entire design cost of which might seem high. A circuit is presented hereby is of disco light making use of low-cost CMOS chip CD4011B, which is a two-input quad NAND gate. Along with two particular gates; G1 and G2 as shown in the figure below, it works as an RC oscillator forming clock oscillator gates. Circuit Description of Disco Light Circuit Here the two input terminals of the CMOS chip are coupled together to form an inverter. And, again…

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