Transmitters

1570

Circuit Mini FM transmitter – video assembly instructions

Instructions, how to build a mini station from cheapest simplest components. Either frequency, modulation, FM (frequency modulation), sends the component values ​​at around 100 MHz Mini Transmitter Instruction Building a super spy bug transmitter.

The 20k resistors together with the resistance of the condenser microphone sets a voltage divider composed of the (dc) operating point of the transistor. Since the resistance of the microphone capsule to the beat changes of the sound waves, does this change and the operating point of the transistor, or in other words, the transistor amplifies the low-frequency voltage to the (electret) microphone comes in a common emitter circuit, the low-frequency signal is at the base and is amplified by the transistor.

Simultaneously, the transistor amplifies the RF signal but also in basic circuit. A small portion of the vibration of the oscillator circuit from the collector (amplifier output) on the 5.6 pF capacitor to the emitter (high-frequency amplifier input of the base) is fed back, the drive current Fliest from the emitter to the base and then 3.3 on the nF capacitor to ground. The capacitor on the basis of mass must be small enough that it does not hinder the low-frequency audio signal, but also large enough that the high-frequency, virtually unhindered tiles to ground. The 470 ohm resistor at the emitter stabilizes the operating point and sets the input resistance of the base circuit.

The whole thing is rather something like an emitter circuit audio amplifier circuit combined with a basic high-frequency amplifier with only one transistor.

How make a wooden FM Transmitter - Circuit FM transmitter mount unusual - a piece of wood with nails - No pcb and solder

How make a wooden FM Transmitter – No pcb and solder

In this video we are showing you how to make a FM transmitter Bug using 2 transistors and a wood circuit board.

The reason for author make FM transmitter this from wood is because  people that can not make there own circuit boards ,can not solder or can not find the capacitor trimmer for adjusting the frequency, well good news this FM transmitter can do without all that ! so i made the circuit board from nails and wood!

This FM transmitter Bug is very easy to build.

Parts used:
Home made wood circuit board !!!
2N3904 transistors x 2
1nf ceramic capacitor
100nf ceramic capacitor
10pf ceramic capacitor
33pf ceramic capacitor
22nf ceramic capacitor x 2
1 – 5p to 30p air trimmer
470R resistor
10K resistor
47K resistor
68K resistor
1M resistor
10mm Mic
175cm antenna
Battery Plug
Some solder

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1062

RFSim99 download free RF simulation and design radio filters software

RFSim99 is a free-ware software that can help you in RF simulation, in your projects, especially if you are trying to design radio filters.

RFSim99 download free RF simulation and design radio filters software

RFSim99 works with S-parameters. This means that not only will it simulate and analyze circuits built out of its internal library of components, but that it can accommodate any circuit block or stage for which these are known. RFSim99 is a free linear S-parameter based circuit simulator offering schematic capture, simulation, 1 port and 2 port S-parameter display and file support, tolerance analysis, stability circles, and much more. Requires Windows 95, 98, NT or 2000.

RFSim99 download free RF simulation and design radio filters software

Download RFSim99