This is a simple 2N2222 transistor based radio FM transmitter circuit within the FCC (Federal Communications Commission) limit, that is no license is necessary for using thisstable FM transmitter circuit. What is an FM transmitter FM stands for Frequency Modulation andFM transmitter is a radio frequency (RF) transmitter which uses frequency modul
Click here to download the full size of the above Circuit.
ation of audio signals. Frequency modulation means that the frequency of a carrier signal is changed according to the input audio signal. The portable FM transmitteris able to transmit sound or music to any standard radio FM receiver. The range of this transmitter is near to 120 meters. Audio signal is applied via a condenser micro phone, which is a capacitive sound sensor. Simplicity and portability makes this transmitter circuit superior to other FM transmitters. The transmission frequency of this FM transmitter can be adjusted using the variable capacitor C7. The main applications of this circuit includesFM transmitter for car, walky talky, wireless audio transmitteretc. The signal from the condenser microphone is passed through a coupling capacitor C1 and amplified by transistor Q1, which acts as a pre amplifier. The amplified signal is applied to the base of transistor Q2. R2 and R6 provide necessary biasing to the amplifier transistor Q1 (2N2222). Amplified sound signal will be available at the collector of Q1 and it coupled to the base terminal of transistor Q2 via the capacitor C3 and R4. Q2, C7 and the inductor forms a RF oscillator circuit that operates in the 80 to 130 MHz range, which is voltage controlled oscillator so its frequency can be modulated by the input audio signal.
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: