Radio Circuits

Click here for Electronic Circuits main page
 

FM transmitter            Click here for the circuit diagram

 Colpitts oscillator. Its frequency depends on the capacitance of the vary cap diode. The center frequency is changed by varying the biasing voltage of the vary cap through the 47K pot. You can use a 75cm telescopic antenna or simply a length of hook-up wire. Mine worked fine with a 6cm hook-up wire and gave a range of 100m with a good FM receiver. The approx. cost of the circuit is around Rs.35

Coil Details (Print on the PCB itself)

The coil shown below can be constructed on the PCB itself as PCB track. Just transfer the dimensions on a copper board and etch it. If the 1mm spacing is difficult use a sharp blade to remove unwanted copper.
You can also use a copper wire and construct a square spiral of the dimensions shown below. Please note that a small deviation from the given dimensions is permissible.
Note: You can even try a coil made of 18SWG copper wire of 5 turns and  5mm dia with air core. The center tap can then be taken at the 2nd or 3rd turn.( I have'nt tried it tell me if it works well)

coil

 

 

Home | Electronics Design | Tutorials | Submit a Circuit | Newsletters | Discussion Forum | Links | Downloads | Contact


Disclaimer: All the information present on this site are for personal use only. No commercial use is permitted without the prior permission from authors of this website. All content on this site is provided as is and without any guarantee on any kind, implied or otherwise. We cannot be held responsible for any errors, omissions, or damages arising out of use of information available on this web site. The content in this site may contain COPYRIGHTED information and should not be reproduced in any way without prior permission from the authors.

Copyright © 2011 - All rights reserved.