February 2009

Home Circuits

Plant moisture level monitor

Description. Here is a simple circuit that will give a visual indication when the soil water level inside your flower pot goes low below a certain limit. The U1C and associated components are wired as an oscillator producing a 2KHz square wave. This square wave is given to one gate input of U1D via a […]

Switching Circuits

Intelligent trailing switch.

Description. This is a very simple yet effective circuit in which the equipments connected at the so called trailing sockets will run only if the equipment connected at the control socket is switched on. For example, let’s connect a motor is connected to the control socket and a lamp is connected at the trailing socket.

Gadget Reviews

Sony Vaio-VGN CR36 Notebook

SONY-The name speaks “Quality” and VAIO speaks “Brand”. I am using this notebook for the last one year and am more than satisfied with its performance. Sony Vaio VGN CR36 is an awesome model with a simple but hot design and cool performance. Specifications-Vaio VGN CR36 Processor– Intel Core 2 Duo-T8100-2.10Ghz Memory – 2GB HDD

Radio Transmitters, Telephone Related

Telephone transmitter

Description. This is a simple, but very useful circuit that can be used to transmit telephone conversations. When the telephone receiver is on hook the voltage across the lines will be about 48 volts. The preset R7 is so adjusted to obtain a 24.7 V across between the cathode of D2 and ground. At this

Radio Transmitters

Long range AM transmitter.

Description. Here is the circuit diagram of an easy to build long range AM transmitter circuit based on three transistors.With correct tuning and a matching antenna, the transmitter can deliver signals up to a distance of 2 kilometers. The audio signal to be transmitted is given to the base of the transistor Q1 via the

Switching Circuits

Sound operated flip flop.

Description. Here given is a circuit in which the status of the output pins of a Flip Flop IC can be toggled by using sound. A condenser microphone is used for picking up the sound. The first two op-amps in the IC1 LM 324 is used to amplify the sound picked by the condenser microphone.

Remote Circuits

Ultrasonic switch

Description. A different type of remote control circuit employing ultrasonic signals is given here. The transmitter part of the circuit is build around IC1(NE 555).The IC1 is wired as an astable multi vibrator operating at 40KHz.The output of IC1 is amplifier the complementary pair of transistors ( Q1 & Q2) and transmitted by the ultrasonic

Sensor Circuits, Tone generator circuits

Water Sensor Circuit with Alarm

If you are looking for a Water level indicator or a Water level controller, there are pretty good circuits we have developed. This one is just a fun project made for hobby purpose! You can call this a water sensor circuit for sure! Description. This is a simple musical alarm circuit which produces a musical

Lighting Circuits

Mains operated LED night lamp

Description. Here is a simple and powerful LED based night lamp circuit that can be operated directly from the 230V mains supply. The are total 24 white LEDs used and the lamp produces an output of around 15W.The resistance R1 and capacitor C1 provides necessary current limiting. The circuit is sufficiently immune against voltage spikes

Home Circuits, Lighting Circuits, Security & Saftey

Night security light

Description.  Here is a simple circuit switches on a light around 2 hours after midnight, the time at which most of the robberies taking place. This simple circuit is build around a CMOS IC 4060 to obtain the required timing. During day time the LDR has low resistance and keeps the pin 12 of the

Tech News

The upcoming era of Video Telepresence

A  recent Gartner Inc survey reveals the upcomong boom in the global industry, Video Telepresence which may kill or damage the Airline and Hospitality business drastically. They say “Video Telepresence will replace 2.1 million airline seats anually” which’s damn serious to airline giants. As a side effect, it will also affect the Hospitality businesses and

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