Circuit-Zone.com - Electronic Projects
Posted on Friday, December 13, 2013 • Category: LED
I like the idea of using LED Christmas lights because they look cool and consume very small amount of electricity, but the flicker drives me crazy! That's because they are powered directly from 110V AC voltage instead DC voltage which makes them flicker 60 times per second. Here is a simple circuit that will completely eliminate LED Christmas lights flicker. The solution is to convert AC to DC voltage with resistor, rectifier diode and capacitor. Using 470 ohm - 1K resistor is very essential because it limits the current to 20mA and minimizes the voltage to about 80 volts. If we didn't use the resistor LEDs would be powered by over 50mA of current which is much more than what they need and that would definitely shorten their life. Note that lowering voltage does not reduce the brightness of the LEDs because when powered by DC voltage they are always on.
Posted on Thursday, December 12, 2013 • Category: FM Transmitters
Here is a very interesting and simple FM transmitter used to transmit audio in the wide range up to 100M using only one transistor. The entire circuit of FM transmitter is divided into three major stages oscillator, modulator and amplifier. The transmitting frequency of 88-108 MHz is generated by adjusting VC1. The input audio generated by microphone is changed into electric signal and is given to base of transistor T1. Transistor T1 is used as oscillator which oscillates the frequency of 88-108 MHz. The oscillated frequency depends upon the value R2, C2, L2 and L3. Transmitted audio from FM transmitter circuit can be received by standard FM receiver.
Posted on Monday, December 9, 2013 • Category: Audio DAC
This DAC is based on latest 32bit/384K PCM5102 DAC chip and DIR9001 from Texas Instruments. Sound quality produced by PCM5102 DAC is surprisingly good, very smooth and airy, with great dynamics and excellent soundstage. It features both S/PDIF and optical inputs connected to DIR9001 low jitter digital receiver. PCM5102 uses a next generation architecture based on the PCM1792/4 TI's flagship DACs. It has 112dB SNR, with an integrated negative rail charge pump and line driver, so you don't need no opamps at the end or dual split supplies. Just a simple RC low pass filter is all that is needed. In addition, there's a fancy PLL involved that will autodetect I2S rate, configure the device, and generate it's own internal master clock so no need for external clock. Entire DAC is powered by only 3.3V from 1117-33 regulator and consumes only 20mA of power. Although PCM5102 DAC can be powered by 4-12V DC voltage, it's recommended to power it from a single 3.7V LIPO battery to achieve the best performance.
Posted on Thursday, November 21, 2013 • Category: FM Transmitters
This is simple FM transmitter for FM broadcast band in 88-108 MHz. BC 549 is small signal transistor for wide applications, but usually for AF. You can build simple FM transmitter with one BC549 transistor and several other component parts. Simple FM transmitter with only one transistor is often called “bug”. This project is suitable for beginners in radio amateur, education, or hobbies. As an antenna you can connect 150cm of copper wire.
Posted on Wednesday, October 16, 2013 • Category: FM Transmitters
A simple MP3 FM transmitter circuit shown here can be built easily in few minutes if all parts are available to you. All the components used in this transmitter circuit are general purpose and low cost. The circuit will work as a best FM transmitter for simply broadcasting your music around your house and yard, and can be used to broadcast the output of any equipment like mp3 player, ipod, satellite, etc.
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