Electronic Projects   |   Store   |   Schematics   |   Downloads   |   Search  

Circuit-Zone.com - Electronic Projects



Portable FM Transmitter
Posted on Sunday, September 1, 2013   •   Category: FM Transmitters


This portable FM Transmitter is easy to build. I have used a pair of BC548 transistors in this circuit. Although not strictly RF transistors, they still give good range. Transmitter is powered by 9V battery. The coil L1 consists of 7 turns on a quarter inch plastic former with a tuning slug. The tuning slug is adjusted to tune the transmitter. Actual range on my prototype tuned from 70MHz to around 120MHz. The aerial is a few inches of wire. Lengths of antenna wire should be 1 - 2 feet. The circuit is basically a radio frequency (RF) oscillator that operates around 70-120 MHz. Audio from audio jack is fed into the audio amplifier stage built around the first transistor. Output from the collector is fed into the base of the second transistor where it modulates the resonant frequency of the tank circuit by varying the junction capacitance of the transistor. Junction capacitance is a function of the potential difference applied to the base of the transistor. The tank circuit is connected in a Colpitts oscillator circuit.

   Portable FM Transmitter

 

Build Accurate LC Meter and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging and reset function to make sure the readings are as accurate as possible ... [more]



Circuit-Zone.com © 2017. All Rights Reserved.
AC / DC Innveters
AM Radio
Amplifiers
Antennas
Arduino
Audio Attenuators
Audio DAC
AVR
Battery Chargers
CNC Milling Devices
Counters / Frequency Meters
Fluorescent Lamps
FM Radio / Receivers
FM Transmitters
Frequency Wave Generators
Headphone Amplifiers
iPOD Hacks
LC Meter
LED
Miscellaneous
Motor Controllers
MP3 Players
Oscillators
Oscilloscopes
PC Circuits
PCB
Phone Circuits
PIC
PLL Circuits
Power Supplies
RC Servo Motors
Remote Control
RF Radio Frequency
Robots
Sensors
Solar Circuits
Stepper Motors
Stereo Encoders
Test and Measurement
Timer Circuits
TV Transmitters
USB Circuts
USB Interface Adapters
USB Soundcards / USB Headphones
Video
Volume Control