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 […]
Simple Battery Level Indicator Description Here is a easy to build low battery level indicator circuit that produces a visible indication by flashing a LED when the battery voltage drops below a predetermined voltage.The circuit is based on Panasonic’s IC MN13811G  and a efficient flasher based on transistors Q1&Q2.Here when the battery voltage drops below
A Simple Light activated switch Description. This is the circuit diagram of a light activated switch based on National Semiconductors comparator IC LM 311 and a LDR. The circuit is based on a voltage comparator circuit wired around IC 1.The non inverting in put of IC1 is given with a reference voltage of 6V using
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
Audio Level Meter Description A simple and low cost audio level meter circuit that can be used to measure the audio level of your sound source.This circuit is a valuable tool for those who are interested in audio circuits. The circuit is designed with a flat frequency response in the range of 20Hz to 50Khz.
Simple AM Transmitter Transmitters are devices that are capable of transmitting audio as radio waves from an audio device. There are two types of transmitters; FM & AM. We have many posts on FM transmitters, so we decided to make one on AM transmitter. AM transmitters create radio waves using Amplitude Modulation (that’s why AM).
Single chip FM transmitter An FM transmitter is a device that can transmit audio from an audio device as a radio signal. Doing so allows the audio to be picked up and played by an FM radio in the transmitter’s range. The FM (frequency modulation) device allows the waves to move in predefined frequencies so
Hi Fi Amplifier Circuit – 2X12 Watts HiFi or High fidelity is a term used to indicate equipment that reproduces a high quality of sound. The highlight of Hi-Fi equipment is inaudible noise or distortions and a natural frequency response. Hifi amplifiers are known to create sounds with utmost clarity so it is a dream of all
Mini Amplifier Circuit Audio amplifiers are electronic amplifiers that are used to amplify weak audio signals from an input like a mic to high amplitude signals to be reproduced through loudspeakers. This is a very simple hobby project suitable for beginners. This homemade mini amplifier circuit is suitable to hone your soldering skills and show off
Remote control tester Circuit Description This is a simple remote controller tester circuit based on infrared sensor IC TSOP 1738. When the IR waves fall on the sensor it output changes to low state. This makes the transistor Q1 (BC558) ON and LED will blink according to the code contained in the signal. So for
12 Watts Transistor Amplifier Circuit Description The circuit shown below is not at all expensive as the amplifier contains only an op-amp and four transistors (easily available from your electronics junk box). Here the op-amp used is uA 741 which produces the required gain. The four transistors are wired as complementary Darlington’s which produces the
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
In this article, we list different burglar alarm circuit and projects we have designed and published in CircuitsToday. A burglar alarm is basically an intruder alert system used to prevent theft/robbery and protect one’s premises. Burglar alarms or alert systems can be designed in different ways; from very simple sound alarm system to the advanced
In this guide, we’re building a fun project (well, ‘tweet’ generating circuit is obviously fun to build, but tweet crossover reduction is purely geeky!)Â – which is a Tweeter Crossover Circuit. This simple design is developed using two capacitors and a potentiometer. Very easy to build and you gain lots of concepts in crossover reduction
In this article, we teach you how to design a simple Lead Acid Battery Charger circuit using an op-amp IC and some associated components. The core of this circuit is IC LM 317 – which is basically an operational amplifier IC. Apart from the IC, a transistor (BC 548) is used to control the charging
Audio Distortion Meter An audio distortion meter is used to measure distortions in, yes you guessed it right, audio. At certain frequencies the sound from most audio devices distorts, they become unclear. Of course, the frequencies and the level of distortions vary from device to device. A distortion meter helps to find the level of
Audio Watt Meter How do you measure the power output of an amplifier? using an Audio Wattmeter. the name Audio Watt Meter’ is a collective name for all devices that are used to measure the output of an amplifier, so many kinds of equipment fall under this category. What we intend in this project is
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
In this project circuit, we’re building a Direct Coupled Radio Circuit using an inductor and 3 transistors mainly. This is a very basic, low cost, hobby purpose circuit – just for the learning purpose of “direct coupling” method. If you’re looking for a good radio circuit, you’d be better off with our FM Radio Circuits
In this guide, we are designing a Liquid Level Switch using 3 transistors (BC107), some passive components, a diode and a couple of relays. This is basically a level sensing circuit designed using minimal components. If you’re looking for an efficient level sensing circuit, you would be better off with our water level controller circuit.
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
Seven Segment Counter Display Circuit Description Here is the circuit diagram of a seven segment counter based on the counter IC CD 4033. This circuit can be used in conjunction with various circuits where a counter to display the progress adds some more attraction. In this circuit a 7-segment display is connected with two NE555
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
Metal Detector Circuit I always wanted to make a metal detector seeing how cool it was in all Hollywood, Bollywood movies. One thing I realised is; things aren’t as difficult as you think it is. After all, I found that a metal detector is really simple and easy to make. So in this post, I
