This circuit is useful to detect microwave (gigahertz signal) sources like microwave oven, satellite communication devices, Mobile phones etc. It gives audio visual indications when it detects the Microwaves in the Gigahertz band. Microwave is the form of EM radiation with frequencies between 2 GHz and 300 GHz. Microwave oven uses UHF around 3 GHz
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in the S band. Mobile phones and Satellite devices generally use 2 to 3. 5 Gigahertz signals. The circuit exploits a few simple scientific facts about EM radiations and Magnetic induction. Electromagnetic radiation has both electrical and magnetic field components which oscillate in phase perpendicular to each other to the direction of energy propagation. If an inductor coil with a parallel capacitor is placed in the path of EM radiation, the capacitor stores electrical energy and inductor stores energy in the magnetic field induced by the coil windings. The magnetic field induces a current in the inductor through` Skin Effect`. This phenomenon is exploited in the circuit to detect the energetic microwave radiations. A pickup coil (L2) with a capacitor (C2) forms the signal detector which resonates in response to the microwave radiation and generates a minute voltage (around 2 milli volts) along the signal diodes D1 and D2. Since the voltage generated by the sensor assembly is too weak, a differential amplifier (IC1) is used to amplify the signal. CA 3130 (IC1) is designed as a differential amplifier with balanced inputs set by R1 and the sensor assembly. The pickup coil is directly coupled to the inverting and non inverting inputs of IC1, so that a minute current in the pickup coil can generate a potential difference across the inputs of IC1 and its output switches high. CA 3130 ( IC1) is a CMOS version high speed...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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