Posted on Monday, April 4, 2011 • Category:
Miscellaneous
Here's a simple microphone amplifier based around TDA7050 IC. There are many schematics, the choice fell on the amplifier chip TDA7050, the only downside was it that it was not appointed to the microphone. By adding a resistor R1 in the scheme by 4,7 kOhm - amplifier can no longer work with conventional condenser microphones.
If you remove the resistor R3 - the alarm will be put on a small speaker with an impedance of winding 32 Om'a.
Voltage amplifier is powered by 3 - 5 volts, but as the amplifier must be nourished from 12 in the scheme of linear stabilizer was added at 5 V.
This scheme was checked with headphones (current consumption was 50 mA) and connect to the line input of your TV.
Posted on Sunday, April 3, 2011 • Category:
Amplifiers

The amp described on this page, is a very simple poweramp based on the National Semiconductor chip LM3875. According to National it's a chip meant for TVs, compact stereos etc. But many people claim that these chips are great high-end amps...
So I decided to try building one. The "design" work was quickly done, as I just used the guidelines and sample circuit of the datasheet. I designed a small PCB for the amp (I'm lazy), and I made it double sided to make it easier to keep all the ground lines separate, as recommended by National.
The prototype board can be seen below with a 100VA toroid I used for testing.
Posted on Sunday, April 3, 2011 • Category:
Headphone Amplifiers

Presented here is a Class A headphone amplifier built around OPA134 opamp and IRF510 MOSFET power transistor as output stage and current driver. Quality, sound engineering applications, the most important criterion. Although many criteria used in the definition of quality for Class A amplifier. The most important feature, new crossover and work conditions and very low intermodulation distortion characteristics of a sound is very close to nature. Audio gurus know very well that the sound of a class A amplifier is the best one you can ever get.
Posted on Saturday, April 2, 2011 • Category:
Power Supplies

I'm replacing my old power-hog home server with a new one based on the Intel D945GSEJT mainboard. This board is essentially a netbook platform that's been "desktopified". Among it's weirder points are that it uses the Mobile 945GSE chipset, SODIMM ram, 44PIN IDE, and that it runs off a single 12V supply. The reason I chose this board is that it consumes 13W in idle and 18W under full CPU and GPU load which is pretty much the lowest power consumption one can get with an Atom system (excluding some server-specific boards that were beyond my budget). Not wanting to use an ATX PSU I've decided to build a completely new power supply for the board. Not having to bother with all the voltages needed for ATX makes this a lot easier. I've decided to make a high-amp 12V supply, and a 5V supply capable of driving two HDDs.
Posted on Wednesday, March 30, 2011 • Category:
Amplifiers
This 200W MOSFET Power amplifier is suitable for many applications such as Guitar Ampplifier, Mic or Home theater.
As many people prefer because of its legendary robustness of MOSFET transistors. MOSFET amplifier is rated at 200W power with 4Ω speakers. It has good frequency range of 1 dB 20Hz up to 80kHz. THD is less than 0.1% at full power and signal to noise ratio when compared to 200W is better than -100 dB unweighted.
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