Audio

FM transmitter for smartphone MP3 Player 2N2218 LM741

FM transmitter for smartphone MP3 Player 2N2218 LM741

Evolution FM transmitter with 2n2218 with audio amplification step using LM741 op amp with audio input for MP3, MP4, mobile, computer and other audio sources, … Read more

Circuit adjustable bass filter from 50 Hz to 150 Hz NE5532

Circuit adjustable bass filter from 50 Hz to 150 Hz NE5532

This is a bass filter, using the OpAmp Ne5532 or another of your choice. The circuit is simple to set up and already has symmetrical … Read more

Power amplifier TDA7297 3D board

Stereo Power audio amplifier with TDA7297 – 2 x 15 Watts

complete stereo amplifier circuit including printed circuit board to power of 2 X 15 Watts. Using minimum of components in the integrated circuit TDa7297 ST … Read more

stereo audio amplifier lm386 PCB 3D board

Simple Circuit – Stereo audio amplifier with IC LM386

This is an audio amplifier with 2 LM386 integrated circuits. Basically it deals with the use of 2 amplifiers as in another article posted at … Read more

Power Amplifier with Subwoofer – TDA2030 and Ne5532 – 2 x 18 Watts + 30 W Bass

Power Amplifier with Subwoofer – TDA2030 and Ne5532 – 2 x 18 Watts + 30 W Bass

This circuit is typical of systems sold for 2.1 PC surround systems, left and right channel and subwoofer. Just plugging in the stereo audio and … Read more

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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Circuit power amplifier stereo audio with LM1875 – 2 x 20 watt

This is an audio amplifier circuit using integrated LM1875 stereo to 2 x 20 Watts. With power supply for ease of assembly for any hobbyist. … Read more