Diagram Diagosis

This is a one watt home stereo amplifier module project using the KA2209 IC from Samsung, which is equivalent to the TDA2822. It operates from 3-12V DC & will work from a battery since the dormant current drain is low. It requires no heat sink for normal use. The input & output are both ground referenced. Maximum output will be obtained with a 12V power supply & 8 ohm speaker, however it is suitable for driving headphones from a supply as low as 3V.

The Specifications of the home stereo amplifier :

D.C. input : 3 – 12 V at 200 – 500 mA max
Idle current : approx. 10 mA
Power output : > 1 Watt max. 4-8 ohms, 12V DC
Freq. Resp. : approx. 40 Hz to 200 kHz, 8 ohm, G=10
THD : < 1 % @ 750 mW, 4-8 ohm, 12V
Gain : approx. x10 (20 dB) OR x100 (40dB)
S/N ratio : > 80 dB, G = 20 dB
Sensitivity : < 300 mV, G = 20 dB
Input Impedance : approx. 10 k ohm

Description 

The gain is adjustable from ten to 100, i.e. twenty to 40 dB. Start with feedback resistors R1 and R3 of 1k ohm, this will give a gain of ten which ought to be adequate for most applications. In case you need more gain, you can remove resistors R1 and R3.This will give a gain of about 100, or 40 dB.The input attenuation can be adjusted by the potentiometer which can be used as a volume control. The IC gain ought to be kept as low as necessary to accomplish full output, with the in put potentiometer and your signal source at maximum.

Voltage Gain = 1+ R1/R2 = 1+R3/R4, however the maximum gain with no outside feedback is about 100, or 40dB. (GdB = 20log Gv)

This will keep the signal to noise ratio as high as feasible. Additional gain provided by the amplifier will reduce the S/N ratio by a similar amount, since the input noise figure is constant. Other values for R1 and R3 of between 1k and 10k ohm can be used if an intermediate gain level is necessary.

If driving a pair of headphones, you may also need a 100 ohm resistor in series with each output to reduce the output level, depending on headphone impedance & sensitivity. Make positive you start with the volume right down to check. Numerous headphones may be driven from the amplifier in the event you wish, since most headphones have at least 16 ohm impedance, or more often 32 ohm.

There are only a few outside parts, the IC contains most of the necessary circuitry. R1,R2 and R3,R4 are the feedback resistors. C1 provides power supply decoupling. C2 and C3 are the input coupling capacitors, which block any DC that might-be present on the inputs. C4,C5 block DC in the feed back circuit from the inverting inputs, and C6,C7 are the output coupling capacitors. C8, R5 and C9,R6 act as Nobel networks providing a high frequency load to maintain stability at frequencies where loud speaker inductive reactant may become excessive. The pot provides adjustable input level attenuation.

Home theaters are getting to be extremely popular among American homes. This modern technology is slowly giving movie theaters a run for their money. Basic knowledge of home theater system and its basic components may be best for people who want to bring home relaxation and entertainment. 

The most important consideration in the design and complete set up of your home theater is the size of the room. The home theater speakers and the other components of your home theater may need to consider the size of the room. Too small rooms for your home theater may not require so many speakers. Only three speakers may be good if the room is quite small. 

Do not overload your small room; you may not be able to get the entertainment and relation you want if you feel overloaded with so many home theater speakers. Because you only need three home theater speakers in your small room, you may need to acquire the high-end brand of home theater speakers to compliment the size of the room and the other equipments for your home theater.

If you have a bigger room however, the basic three home theater speakers may not be enough. You may need to put up to six speakers around the room, you may also consider complimenting your home theater speakers with subwoofer to complete the surround sound like in movie theaters. In addition to the speakers, you may also need to purchase a high-end television set which should not be smaller than 27 inches. It may not be reasonable if you buy a smaller television set because it may drown in the fineness of your home theater speakers.

Additionally, the DVD player needs to be of high quality, having progressive scan your DVD Player may help provide sharp images and flicker-free pictures for your home theater system. The home theater speakers, television and DVD player are the basic components of a home theater system especially if the room is quite small. However, for bigger room, adding home theater furniture and home theater projectors may be necessary to complete the package. Again, it may be worth it, if your home theater speakers are of high quality. This is because of the need to provide a surround sound for the home theater set up. The DVD player and the television set may answer for the requirement of sight in a movie theater setup. Your home theater speaker needs to answer for the sound requirement, and if your home theater speaker is not of high quality brand, it may not be able to do the job for you.

In order for you to avoid making mistakes in your choice of home theater equipments including home theater speakers, and home theater furniture, you may require the services of a home theater designer. They will be able to provide the best recommendation that will ensure you will get the most out of your home theater system including topnotch home theater speakers. Additional home theater furniture may be necessary to complete the package and to dress up the whole room. Since they are the designers, they will be able to recommend the best for your home theater system set up. If you have a properly designed home theater, you will be the best entertainment possible.

Your home theater designer may take on the huge responsibility of choosing the most suitable home theater speaker to attain the best design for your home theater.

Bring home relaxation and entertainment right in your own living room, home theater system can provide this to you and your family.

The application of voltage instantly starts transforming one surface of the unit hot and the reverse surface cool very fast.
However, the hot end must be quickly managed so that the heat does not reach higher levels, which can completely hamper the heating and cooling process and ruin the device itself.

Therefore the hot surface must be attached with heavy heatsinking materials like aluminum or copper metal of suitable sizes.The simple construction of a simple peltier refrigerator shown in the figure demonstrates the above discussed set up where two such devices are appropriately fixed with aluminum plates for radiating different degrees of temperatures from their relevant sides.

The plates responsible for generating the cooling effects must be trapped inside a well insulated enclosure made up of thermocole or polyurethane foam etc.

The inside chamber may be used for storing water bottles or water packets as desired.

The hot heatsinked surfaces must be exposed in the outside air for radiations and for controlling the temperatures of "hot" ends of the unit, see figure.