Description. Many fire alarm circuits are presented here,but this time a new circuit using a thermistor and a timer to do the trick. The circuit is as simple and straight forward so that, it can be easily implemented. The thermistor offers a low resistance at high temperature and high resistance at low temperature. This phenomenon […]
Description. The circuit diagram present here is that of a street light that automatically switches ON when the night falls and turns OFF when the sun rises. In fact you can this circuit for implementing any type of automatic night light. The circuit uses a Light Dependent Resistor (LDR) to sense the light .When there
Description. Here is the simplest scheme for converting a CD ROM drive of your computer to a Audio CD player. The minimum requirement for the player is that, it should have a audio output and skip button. Luckily most of the CD ROM’s are equipped with both of these. Â The CD ROM drive needs two
Description. Here is a simple fire alarm circuit based on a Light Dependent Resistor (LDR) and lamp pair for sensing the fire. The alarm works by sensing the smoke produced during fire. The circuit produces an audible alarm when the fire breaks out with smoke. When there is no smoke the light from the bulb
Description. This straight forward circuit will protect electrical appliances from over voltage as well as under voltage. The circuit also produces an alarm when the power supply comes back. An ideal circuit for home to protect your valuable equipments from voltage fluctuations. The same circuit with some modifications can be used to make a automatic
How to make a 12V battery charger at home? Description Here is the circuit diagram of a simple and straight forward 12 V battery charger circuit with diagram. This circuit can be used to charge all type of 12V rechargeable batteries including car batteries. The circuit is nothing but a 12V DC power supply with
Description. Here is the circuit diagram of a simple yet interesting mini organ based on UJT 2N 4891 (Q1). You can produce the desired sound by pressing each pushbuttons. You have also the option to set each push button to produce the desired tune you want. The circuit is based on a UJT oscillator who’s
Description. Almost all liquidator type mosquito repellers are rated 5Watts. It is a pretty energy consuming game when these repellers are operated through out the night. Even though these liquidators are switched ON and OFF in discrete intervals there will be no considerable loss in the effectiveness, and more over there will be a great
With this cool cat/dog repeller circuit you could chase the cats off from any where you want. In fact, I designed this circuit to chase my cat from my computer table. Most of the animals like cats respond violently to ultrasonic sound and in fact it’s the best way to chase them off. This principle
In this tutorial, we have explained how to build a DIY (Do It Yourself) Infrared Motion Detector Circuit using 555 Timer IC, IR Diode, 2 comparator IC’s and other associated components. An Infrared Motion Detector circuit can be designed in different ways using different sort of components. This one is a low cost, easy to
Description. When there is a fire breakout in the room the temperature increases. This ultra compact and low cost fire alarm senses fire breakout based on this fact. Transistor BC177 (Q1) is used as the fire sensor here. When the temperature increases the leakage current of this transistor also increases. The circuit is designed so
Description. Here is a simple rain alarm circuit that produces an audible alarm when ever rain falls. The rain detector circuit is based on two transistors (Q1 & Q2) and a NE555IC (IC1). The two transistors are wired as a switch which goes on when the base of Q1 is shorted to the positive of
A simple Light to Frequency Converter Introduction. Here is the circuit diagram of a effective light to frequency converter circuit that can be used for variety of applications such as light intensity measurement,fun etc. The circuit is based on TLC555, the CMOS version of famous timer IC NE 555. A photo diode is used for
USB LED Lamp Circuit Description Here is a simple USB powered lamp that can be used to light your desktop during power failures. The circuit operates from the 5 Volt available from the USB port. The 5V from the USB port is passed through current limiting resistor R2 and transistor Q1. The base of transistor
In this project, let’s build a simple Remote controlled switch for appliance controlling. If you know basic concepts of electronics, this circuit is pretty easy to build and test. The core of this circuit are two IC’s – which are infra red sensor IC’s – TSOP 1738. A couple of transistors and associated components complete
Multi-Tone Alarm This multi-tone alarm circuit will help you create a burglar alarm that will not only alert you of intruders but will also play a different tune each time an intruder comes, this makes sure that no regular intruders will have to listen to the same boring tone again and again! 🙂 Kidding aside this
Scream Generator Circuit Scream generating circuit? Well actually this is a simple sound generator circuit, but of course, you can create a screaming sound with it. It has unlimited possibilities in pranks and Halloween, just use your imagination. It works like a car horn or a doorbell but intensity increases the more you keep it pressed.
Super light Sensitive Intruder Alarm Circuit Intruder alarms are popular devices used in high-security areas as well as civilian houses to detect and alarm the presence of any intruders. There are different kinds of intruder detection alarms, some detect movements by using a laser, some use pressure variations etc. Our intruder alarm works using an
Dual Tone Train Horn Circuit – Description A dual tone train horn simulator circuit can be made using two NE 555 timers connected in cascade. Here instead of using two NE 555 timers a single NE 556 timer is used which is nothing but cascading two 555’s in one package and each timers works independently.
Doorbell Circuit Description Related Posts: Melody Generator using UM 66 Door Bell Circuit Using NE555 The main objective of the doorbell circuit is to convert electrical signals (input) into audio signals (output) with a single press of a switch. The circuit given below is a modified version of the Melody Generator Circuit, whose link
Car Battery Voltmeter Circuit Description The main onjective of the car batter voltmeter circuit using LED is to work as a warning inducator using a voltmeter circuit to test the life of car batteries. A voltmeter, though can be bought from a store, is designed as a circuit to make the whole arrangement a lot
In this project guide, we’re building a Touch Switch Circuit using NE 555 IC. As you know, NE/SE 555 is a very popular timer IC with multiple applications in different projects. A touch switch is basically a simple switching circuit activated upon a touch. If you’re new to 555 IC, please take the time to
How cool is it to design an Automatic Car Head Lights Turn Off Circuit? Well, I’ve always fascinated myself by playing with car electronics. And today is my day! I’ve come up with a really cool circuit, where you can turn the car headlights “OFF” after a preset time. This cool circuit is designed using
In this project, let’s learn about automatic wiper control using NE555 IC. As you all know, NE/SE 555 is one of the most common timer IC ever created in the world. There is absolutely no electronics enthusiast who has never played with the 555 IC. We’ve extensively covered 555 IC, where we have a big
Melody Generator Circuit This is a simple project using the IC UM66. UM66 has an inbuilt beat and tone generator. This IC, with its three legs, looks like a transistor. This IC has many versions for playing different songs/beats. This project is suitable for beginners as its circuit is very simple. Description  The UM66 series
