Friday, October 11, 2013

Long range FM voice Transmitter circuit

This circuit shows how to build a super-sensitive, mini-powered FM transmitter consisting of a RF (radio Frequency) oscillator section interfaced with a high sensitivity, wide pass-band audio amplifier and capacitance mike with a built-in FET (Field Effect Transistor) that modulates the base of the RF oscillator transistor. Transistor Q1 forms a relatively stable RF oscillator whose frequency and is determined by the value of coil L1 and turning capacitor C4.
fm voice transmitter

Long range fm transmitter schematic
Part List :
R1_______15K
R2_______3K9
R3_______220R
R4,R5____1K
R6,R9____10K
R7_______390K
C1,C6____0.01uF
C2_______4.7pF
C3_______0.1uF
C4_______6-35pf trimmer cap
C5_______2.2uF
B1_______3V
L1_______Coil winding (see below)
Q1,Q2____PN2222
M1_______Special FET bypassed microphone

Assemble L1 :
Form L1 by tightly wrapping eight turns of #16 bus wire on a #8 wood screw. Produces an eight-turn coil with an inner diameter of approximately 0.135 inches and lenght of about 0.625 inches. Insert in the proper hole and solder as shown.
Long range fm voice transmitter

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.