Dual DC output from single output transformer (+V,0V,-V)

From this circuit you can create a dual power supply from a single output transformer.Voltage regulators are used for controlling the voltage.(any 78XX,79XX)
*use heat sinks for the regulators
*this circuit cannot be used for high power applications like power amplifiers because 78xx series cannot handle a current over 1A.

USB MP3/FM Radio/SD Card Kit

These modules are cheap and simple way of building a MP3 player/FM radio. There are different models with minor differences but all of them has the same basic Input/Output.

• Power: Supply voltage is 5V. Exceeding this voltage will damage the module.
• Audio Output: 2 channels. This circuit requires a separate Audio Amplifier and Speakers (+                               preamp with tone control) .But you can use a headphone without an amplifier.
• FM Radio: Connect an external antenna for better FM reception.

Connections are marked on the PCB.

Use a voltage regulator (7805) in the supply.
Connectors can be changed to your liking.

LM1036 Tone/Volume/Balance Circuit

The LM1036 is a DC controlled tone (bass/treble), volume and balance circuit for stereo applications in car radio, TV and audio systems. An additional control input allows loudness compensation to be simply effected.

Four control inputs provide control of the bass, treble, balance and volume functions through application of DC voltages from a remote control system or, alternatively, from four potentiometers which may be biased from a zener regulated supply provided on the circuit.

Each tone response is defined by a single capacitor chosen to give the desired characteristic.

Features

• Wide Supply Voltage Range, 9V to 16V
• Large Volume Control Range, 75 dB Typical
• Tone Control, ±15 dB Typical
• Channel Separation, 75 dB Typical
• Low Distortion, 0.06% Typical for An Input Level of 0.3 Vrms
• High Signal to Noise, 80 dB Typical for an Input Level of 0.3 Vrms
• Few External Components Required

All trademarks are the property of their respective owners.

*http://www.ti.com/product/lm1036

Application Circuit.

• Cb and Ct capacitor pairs control the Bass & Treble tone response.You can use slightly different capacitors to your liking. Always use good quality capacitors in audio circuits.
• This circuit don't require Stereo Volume controllers.
• Use a good quality power supply (9V - 16V).You can use voltage regulators for better results. (78xx)

I used an old CD Drive as a casing.

Back to Basics:2 LED Blinker

The "astable multi vibrator" is a very simple circuit .Can be assembled on PCB,Breadboard or you can just free solder.I recommend a Breadboard because you can always do experiments.

330  Ω          = 2              

33 kΩ           = 2   

47uf -10v       = 2   larger the value slower the blinking rate

LED            = 2   

C828         =  2  (any general purpose npn transistor is OK)


 

Demo http://gfycat.com/ifr/UntriedGrandAmericanwarmblood

STA540 Power Amplifier

"The STA540 is a 4-channel, class AB audio amplifier designed for high quality sound applications.The amplifiers have single-ended outputs with integrated short-circuit protection, thermal protection and diagnostic functions."

The STA540 is a 4 x 13 W dual/quad power amplifier which I found cheap,easy to build and provides good audio quality with low power consumption.By going through the data sheet you can design your own amplifier with this IC or you can get DIY kits online(Audio amplifier kit from sparkfun ).Use a big chunky heat sink.

For better audio quality use a pre-amplifier with a tone control.

Supply voltage: 8v...22v single DC

Power Output:

– 2x 38 W into 4 Ω at 18 V, 1 kHz, 10%THD

– 2x 34 W into 8 Ω at 22 V, 1 kHz, 10%THD

– 2x 24 W into 4 Ω at 14.4 V, 1 kHz, 10%THD

– 2x 15 W into 8 Ω at 16 V, 1 kHz, 10%THD

– 4x 13 W into 2 Ω at 15 V, 1 kHz, 10%THD

– 4x 11 W into 4 Ω at 18 V, 1 kHz, 10%THD

– 4x 7 W into 4 Ω at 14.4 V, 1 kHz, 10%THD

Application circuit for 2 channels:

 Application circuit for 4 channels:

Application circuit for 2 channels+bridge drive(can be used for a 2.1 system) :

In my project I used an old PC Power Supply as a casing. I kept the PS cooling fan so there is no need to use a large heat sink.

  

CONS:The multiwatt15 package could be problem if you are using a Veroboard.I had to bend the pins to get them aligned with a PCB.
'Apart from that very good chip.