Schematics > RF circuit > A small FM transmitter (SMD)
A small FM transmitter (SMD)This SMD FM transmitter has an operating frequency of about 80 to 115MHz.
Under reasonable circumstances you will be able to receive its signal at a
distance of about 200 meters. Although it is low-power, it might be illegal in
your part of the planet.
Here's the circuit:
Depending on the electret microphone you use, you might have to tweek R4 to
set the gain of the pre-amplifier. Depending on the Q of the LC-part (usually
not very good when using off-the-shelf SMD parts) you may also have to re-bias
the end stage of the circuit. For the coil you can use a
ECM45T Series
Inductor.
You can
download the PCB design here (only 2.5Kb). It's a double-sided PCB in
CorelDraw 3.0 format (zip compressed).
by Oscar den
Uijl, odu@xs4all.nl
Title: A small FM transmitter (SMD)
Source: www.xs4all.nl/~odu/
Published on: 2005-02-03
Reads: 934
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