The figure below shows a schematic diagram of a simple FM receiver. This receiver made with four transistors. The signal from the antenna through the trimmer capacitor C1 goes to the input of the first stage. This stage is a super-regenerative detector based on the transistor T1 circuit. The potentiometer R1 is used to adjust the regeneration. The
Click here to download the full size of the above Circuit.
trimmer C1 is used to adjust the coupling of the antenna to the resonant tank L1C2. An audio signal from the output of the super-regenerative detector through a low-pass filter is fed to an audio amplifier. The filter reduces the noise level at the input of the audio amplifier. The audio amplifier is based on transistors T2-T4. Each stage of the amplifier has a negative AC feedback loop (capacitors C8, C10 and C12). A load of the amplifier is the high-impedance headphones. The coil L1 is wound on a mandrel of diameter 12 mm and length of 10 mm. It contains 3 turns of silver-plated wire with a diameter of 1. 5 mm (AWG 15). The coil L1 is tapped in the middle. With this coil the frequency range is 100. 170MHz.
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: