The ambit declared actuality is that of a metal detector. The opera- tion of the ambit is based on superheterodyning assumption which is frequently acclimated in superhet receivers. The ambit utilises two RF oscillators. The frequencies of both oscillators are anchored at 5. 5 MHz. The aboriginal RF oscillator comprises transistor T1 (BF 494) and a
Click here to download the full size of the above Circuit.
5. 5MHz bowl clarify frequently acclimated in TV sound-IF section. The additional oscillator is a Colpitt ½s oscillator realised with the advice of transistor T3 (BF494) and inductor L1 (whose architecture capacity follow) shunted by trimmer capacitor VC1. These two oscillators ½ frequencies (say Fx and Fy) are alloyed in the mixer transistor T2 (another BF 494) and the aberration or the exhausted abundance (Fx-Fy) achievement from beneficiary of transistor T2 is affiliated to detector date absolute diodes D1 and D2 (both OA 79). The achievement is a pulsating DC which is anesthetized through a low-pass clarify realised with the advice of a 10k resistor R12 and two 15nF capacitors C6 and C10. It is again anesthetized to AF amplifier IC1 (2822M) via aggregate ascendancy VR1 and the achievement is fed to an 8-ohm/1W speaker. The inductor L1 can be complete application 15 turns of 25SWG wire on a 10cm (4-inch) bore air-core above and again cementing it with careful varnish. For able operation of the ambit it is analytical that frequencies of both the oscillators are the aforementioned so as to access aught exhausted in the absence of any metal in the abreast around of the circuit. The alignment of oscillator 2 (to bout oscillator 1 frequency) can be done with the advice of trimmer capacitor VC1. When the two frequencies are equal, the exhausted abundance is zero, i. e. exhausted frquency=Fx-Fy=0, and appropriately there is no...
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.....
characters left: