Free Electronic Circuits & 8085 projects

Electronic projects with circuit diagram and 8085 microprocessor projects.

FM transmitter circuit

Published on Jul 19 2010 // FM Transmitter Circuits


FM transmitter circuit

Making use of TA7335 FM transmitter , achieved very good results . Circuit is simple and practical , firing frequency is very stable, low power consumption, suitable for amateur production . The original circuit block and Q5337, are common in FM tuner with integrated circuit TDA7335 place . TA7335 pin function as follows : 1. foot antenna signal input ; ? foot connected power supply ; ? high level output pin external tuning circuit ; ? pin mixer input ; ? feet to ; ? pin mixer output ; ? pin internal oscillation External LC circuit device ; ?, ? feet between the inside has a varactor diode . When the left and right channel audio signal by R4, R5 mixed input, adjust the signal from the W size, by C7, L3 into ? feet, ?, ? foot capacity of the internal varactor diode varies with the audio signal , thereby changing the foot ? Resonant frequency of an external circuit to realize the frequency modulation of the carrier oscillator . ? pin external components for internal varactor diode to provide a stable voltage . LED doubles as a power indicator . Oscillation signal has been tuned in-house here as input to the mixer amplifier , the output from the ? feet , out through the antennas . When the actual production , L1, 12 are used , 0.5mm enameled wire close around 6 in the ball-point pen heart turn were derived from them in the middle tap L2 . lj for small inductors , resistors can be replaced with lOk . With a soft wire antenna , rod antenna can be . Circuit power , the tuning can change the firing frequency of C1 , C3 to adjust . The strongest emission signal , the role of distances can , in order to reduce interference , the input signal line should be shielded cable.