Buy Circuits Online from CircuitsGallery

With the continuous support we are getting from our readers in the past years, we the i-St@rGroup team are thinking of introducing a new service.

It is our pleasure to announce that we have started an online STORE for buying electronics circuits and projects. 

It includes assembled electronics circuits, school projects ,college projects, electronics components, PCBs etc. at a reasonable rate and minimum home delivery time.

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Simple Two Way Communication Intercom Circuit Schematic diagram

Intercom or Inter communication circuit is a two directional communication system. It provides a reliable communication line and is extremely easy to implement. The circuit is prepared by an amplifier, two switches and two loudspeakers. We can extend this circuit by adding more number of speakers with the help of switches. IC LM384 works as a power output amplifier in this intercom circuit. LM384 provides almost 2 watts of audio power via 15 volts supply voltage. This intercom circuit diagram is very simple and practical circuit capable of using intercoms for homes, office intercom.

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LED dot display based Battery charge level indicator circuit diagram

At many situations we need to display the amount of battery charge through some kind of indication methods like LED dot display or LED bar display. Here CG comes with a battery charge indicator circuit using LED dot display. This battery power level indicator circuit is build around LM3914 IC. It is able to sense voltage levels and is capable to drive a display of 10 LEDs in dot mode or bar mode.

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Simple LM35 Electronic Temperature Sensor Indicator Circuit

This is a simple temperature sensor circuit diagram using LM335 temperature sensor and LM3914 IC. Here the complete temperature range becomes observable through an array of LEDs. The LM35 is an integrated circuit temperature sensor for sensing temperature in degree Celsius scale. The LM3914 is an efficient display driver cum milli volt measuring IC and it is very easy to apply as an analog meter circuit.

In this temperature monitoring system the milli volt output from the LM35 is converted to digital temperature indicator by means of LM3914 IC. The LEDs in this circuit shows the temperature levels digitally via 20 steps. This temperature indicator circuit is absolutely the simplest to build, as it is based on a single stand alone IC LM3914 by Texas Instruments, which executes the entire process of indicating the temperature range.

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Electronic mosquito insect repellent circuit using 555 IC

Mosquitoes are one of the most irritating bugs and they spread many diseases. Wide varieties of mosquito repellents are available. Here we are talking about a method which would most likely drive away the mosquitoes with the help of certain frequency generators. Researchers have found that insects are typically allergenic to a specific spectrum of frequency range called the ultrasound frequency.

This is a simple circuit of ultrasonic mosquito (insect) repeller for insect control based on the theory that insects like mosquito can be repelled by using sound frequencies in the ultrasonic (above 20 KHz) range. This insect repellent frequency is farther than the hearing range of humans, but can cause a lot of nervousness to the insects and also to animals like dogs and cats. Bug control is easy with this best insect repellent.

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Mobile cell phone detector (sniffer) circuit diagram: engineering and diploma project

Here is a simple engineering project circuit of handy mobile cell phone detector (sniffer). This pocket-sized mobile communication detector or sniffer can sense the existence of a mobile device. So it can be used to avoid the use of mobile phones in private rooms, examination halls, etc. It is also useful for detecting the use of mobile phone for spying and other related activities. The circuit can detect incoming and outgoing calls, SMS, MMS, GPRS usage and video transmission even when the mobile phone is set aside in silent mode. The instant bug detects RF (Radio Frequency) transmission signal from a mobile phone, it produces a beep sound alarm.

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DTMF Cell Phone controlled Home appliances- Engineering automation project

Do you think that you can control your home and office electrical appliances using your cell phone? Yes.! you can... Here is a simple home controls home automation electronic mini project circuit diagram for engineering students, to control any electrical appliances using mobile phone without using a microcontroller. This circuit makes use of DTMF (Dual Tone Multi Frequency) technique. We have already posted on What is DTMF and DTMF decoder circuit using M8870 decoder IC.

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Gas Leakage Sensor Alarm Circuit Engineering Project using 555 Timer and MQ6 SEN 1327 Gas Sensor Module

In this article we will be discussing about a home security alarm circuit. This is a LPG gas leakage sensor circuit that detects the outflow of LPG gas and alerts the user via audio and visual indications. The heart of this simple engineering project is a gas sensor module SEN 1327. QM 6 gas sensor is used in this SEN 1327 module. The output signal from this gas sensor module is used to drive a 555 timer astable multivibrator. Here 555 timer works as a tone generator, the frequency of tone can be altered by varying the preset VR1.

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Laser Communication Project Circuit Schematic using LASER Diode and LM386 Low Voltage Audio Amplifier

Here is a wireless LASER communication project for you using LM386 low voltage audio power amplifier circuit. The LM386 is a power amplifier (audio amp chip) IC designed for use in low voltage customer applications. The inside gain is set to 20, but adding of an external resistor and capacitor between pins 1 and 8 will enlarge the gain to any value from 20 to 200. The inputs are ground referenced while the output automatically biases to one half of the supply voltage. The quiescent power drain is only 36 milli watts when operating from a 9 volt supply. Below laser communicator transmitter and receiver schematics are described in detail. Hope this project shows you the importance of laser in communication.

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Numeric water level indicator- liquid level sensor circuit diagram with 7 segment display - Engineering project

Water level indicator circuit or liquid level sensor displays the current level of water in any water tank reservoir. Here we use a simple real time encoding circuit with 7 segment display. It can also be used as a water level meter or water level detector. Combining this project with our previous post ‘Automatic water tank level controller’ will give a complete automated control system for home and industries. This water level sensor consist of 8 to 3 encoder (74148- 8 line to 3 line priority encoder) with some water sensor arrangement. The encoded level is displayed on a 7 segment digital display. This circuit uses one 'Hex display', it does't require driver IC to encode. It makes the implementation simple. You can use '7 segment display' with appropriate driver IC 7447.

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Automatic water tank level controller motor driver circuit- Engineering project without Microcontroller

Automatic water level controller circuit is a simple engineering project. It can automatically switch ON and OFF the domestic water pump set depending on the tank water level. You can implement this motor driver circuit at your home or college using less costly components. The approximated cost of the project is about $5 only. The main advantage of this water level controller circuit is that it automatically controls the water pump without any user interaction.

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