Miniature FM Transmitter
Learn to build your own mini FM transmitter compliments of Cleveland Institute
of Electronics.
This fun project will show you how to build a mini broadcasting device that can
transmit an audio signal up to a quarter mile to any FM receiver. It's easy to
build and a good learning experience and best of all - it's free!
This project was written by one of CIE's instructors. It serves as a hands-on
learning tool for our students or anybody interested in electronics
troubleshooting.
Having a range of up to a quarter mile, it's great for a house security system,
baby monitoring device or simply a listening gadget that you can place anywhere!
C4 is a small, screw-adjustable, trimmer capacitor. Set your FM receiver for a
clear, blank space. Then, with a non-conductive tool, adjust this capacitor for
the clearest reception. Although this transmitter is designed for the FM
broadcast band, it can be tuned to 2 meters, and other VHF bands by changing
values of C4 and L1.
Close up
L1 is 9 turns of #22 gauge solid wire (air-wound) 1/4 inch diameter coil. Use a
1/4 inch diameter bolt and wrap the wire in the threads. After mounting the
coil, back out the bolt.
C1, C2, C3, and C5 are ceramic type capacitors, preferably npo (low noise) or
equivalent. However, you can use any type you have around, but do not use
electrolytic or tantalum capacitors.
A 2N3904 transistor was used for Q1 and Q2. The 2N3904 is a general purpose
silicon NPN bipolar transistor used for switching and amplifier applications.
However, you may substitute the 2N3904 with a 2N2222 or a 2N3906, these are also
general purpose transistors.
Back
The antenna is 8” to 18” of any type wire.
Try to keep all leads as short as possible to prevent stray capacitance.
Transmitter Parts:
R1, R4, R6 10K resistor
R2 1Meg resistor
R3 100K resistor
R5 100 ohm resistor
R7 1K resistor
C1, C2 0.1uf capacitor
C3 0.01uf capacitor
C4 5 - 30pf variable capacitor
C5 4.7pf capacitor
Q1, Q2 2N3904 transistor
L1 9 turns of #22 gauge
Microphone Electret Mic
Circuit Board
Battery Clip
You can buy these parts at any electronics store.
2 NEW Certificate Programs
Cleveland Institute of Electronics created two courses that'll prepare
students for a careers in two growing fields:
Automation/Robotics and Computer Security.
Students graduate with strong problem-solving and analytical skills needed to
design new hardware and software
systems.
Distance Learning Courses
CIE Bookstore has a variety of affordable and convenient distance learning programs
that are ideal for the hobbyist.
They're great for keeping your resume current with the latest technology,
updating your troubleshooting skills or simply learning a new area of interest.
NEW! Digital Electronics DVD Course with Lab
Study at home and learn about Digital Electronics with 12 lessons on DVD and lab exercises. Learn more!
NEW! iPhone Repair Course
Study at home and learn to fix iDevices like iPhones, iPads and iPods. Learn more!
More Distance Learning Courses:
FREE Small Engine Repair Course
Learn to repair and troubleshoot small engines.
AC/DC Basic Electronics - $225
39 lessons with hands on labs.
Circuit Design with NI Multisim - $225
11 lessons with lab.
Electric Circuits with Lab - $275
20 lessons with hands on training lab making circuits.
FCC Exam Prep - $49
19 lessons on CD, GROL prep & more!
Printed Circuit Board Design - $150
4 lessons with hands on lab. Learn PC board layout.
Introduction to Multimeters - $195
4 lessons with hands on lab. 2 multimeters and soldering iron are included.
Industrial Electronics
Computer
Technology
Automotive and Small Engines
Tool
Kits
PC
Diagnostics
Don't know how to solder?
Learn to solder with our
distance learning soldering micro course with lab. The complete
course is $95.
Click here to enroll in the soldering micro course.
Or you can enroll in our
Introductory
Electronics Course - Course 1B. After you complete all 93 lessons & labs
you'll have a firm foundation in electronics technology and you'll get a diploma from CIE to prove it.
CIE is a distance learning school that has been training technicians
with our patented lessons and labs for eighty years. CIE has programs that
cover electronics troubleshooting, computer technology, wireless communications
and networking.
CIE's programs include both theory and hands-on training that will give you the
skills and confidence necessary to start a new career or advance in the one you
already have.
Click here for a
complete list of CIE's courses.
Request a FREE CIE Course
Catalog!