Tuesday, November 18, 2014
FM Receiver TV Tuner TDA7000
This simple one chip FM receiver / TV tuner will acquiesce you to accept frequencies from 70 up to 120MHz. With this baby receiver it is accessible to auto TV stations, absolute 88 - 108MHz FM band, aircraft chat and abounding added clandestine transmissions. It is a absolute accompaniment to any FM Transmitter abnormally if FM bandage in your breadth is actual crowded. TDA7000 receiver offers actual acceptable acuteness accordingly it will alike acquiesce you to auto weaker signals that cannot be heard on accepted FM receivers.
A accurate affection of presented TDA7000 FM receiver is a voltage controlled oscillator agnate to TV tuners that are acclimated in television sets. Abundance is acquainted by capricious the ascribe voltage to the oscillator. The advantage of this blazon of oscillator is that you can use approved 100K potentiometer to absolutely tune to a accustomed broadcast. Tuning can be performed abundant quicker and absolutely than by application a trimmer (variable capacitor). Trimmers will additionally about-face the abundance as you blow them area potentiometer will not. Trimmer additionally needs to be placed on receivers PCB to abbreviate the devious capacitance area potentiometer can be calmly placed anywhere you appetite because it will not be afflicted by any alien capacitance.
Thursday, October 2, 2014
How to Make a Simple FM Radio Circuit
In certain spots 3 steps of music boosting most likely are not needed, wherein situation TR3 and its related parts could be excluded as well as the free end of capacitor C5 linked to the collector of TR2.
The crucial portion of the fm radio receiver is the initial stage, TR1/VC1, in which the wirings needs to be kept as tight as they can. Coil L1 is established by winding 8 turns of 1mm (20 swg) enamelled copper wire on a six mm diameter former, that may be in that case eliminated. Following that L1 must be extended cautiously and uniformly to a length of about 13mm.
Transistors List
TR1 = BF199
TR2 = TR3 = TR4 = BC547
The tunning capacitor VC1 is among the 2 fm areas of a tiny fm transistor radio with integrated trimmers (VC2). The “earthy” tail (moving vanes and spindle) is hooked up to the 22pF capacitor C1. The value of the rf choke L2 is not important, whatever from 1µH to 10µH genuinely acceptable.
The output is appropriate for regular headphones linked in series to offer an impedance of 64Ω.
Tuning-in the fm radio receiver
To the radio receiver, potentiometer VR1 should initially be promoted gradually (in the direction of the end of the path linked to battery positive) until, at around the half-way position, an abrupt little rise in background disturbances is going to be heard, suggesting the beginning of oscillation. It after that must be assisted off, extremely steadily, until oscillation simply ceases; it next has to be easy to tweak in a few stations.
The right frequency range of 87 MHz to 108 MHz can be acquired by fine-tuning VC2 at the higher frequency (108 MHz) and somewhat flexing or squeezing jointly the turns of coil L1 towards the end (87 MHz).
FM transmitting is a transmission know-how pioneered by Edwin Howard Armstrong which employs frequency modulation (FM) to high-fidelity audio over broadcast radio. The "FM band" is the "frequency spectrum wherein FM is utilized for broadcasting". This phrase is moderately inaccurate, because it relates a modulation approach with a variety of frequencies.
Thursday, August 28, 2014
FM Transmitter Bug
This is a FM transmitter schema.the spacial thing of this schema is, this schema can be fixed in a small space.The coil is four turns of 18swg wire wound around a quarter inch former.After turning one and a half turns from the supply end tap and fix the aerial.
Note
# This schema is not legal one so dont miss use this.Though you did like that we cant get the responsibility of it.
# This schema can be operated with 9V power supply.
Sunday, August 17, 2014
Build a 9V Wireless Microphone FM Transmitter
9V Wireless Microphone FM Transmitter Circuit Diagram
Saturday, August 16, 2014
FM Jammer Circuit
Here is a Fm jammer schema diagram.This schema transmit VHF signals.Normally powerful oscillation of the schema interrupt FM signals
Note
# Jammers are ban in lots of countries so you shouldnt miss use this and you must assemble this schema on your own responsibility.
#For L1 make 6 turns of 16AWG enamelled copper wire on a 9mm plastic former.
# connect 30cm long wire as the antenna.
