disadvantage of push-pull amplifier is the presence of a large capacitor between the output and the dynamic head.This disadvantage is eliminated in the bridge amplifier consisting of two identical two-stroke working in opposition.The speaker is connected between their outputs.To build such an amplifier chip purchase type TDA2822.The first solder supply its conclusions: the second - to the positive rail, and the fourth and the sixth - to ground.Between the positive bus and the common wire, set the correct polarity, the electrolytic capacitor of 1000 uF, rated at not less than 16 V. In parallel to it, connect the ceramic or paper of any capacity.
Gather input amplifier circuit.To do this, take a variable resistor with a characteristic type B, having a resistance of 100 kilos.Put it to his conclusions, the handle upwards.The left pin is
connected to ground, the middle - with a central contact input jack, and remove the right signal to be supplied to the amplifier through capacitor 10 uF, rated at not less than 10 (the negative plate of the regulator).Plus-liner of the capacitors are connected to the seventh terminal of the chip and the housing input jack - to ground the amplifier.Also, between the seventh and the total output of the chip resistor wire turn 10 kilos.
Collect corrective chain.For this purpose between the eighth and fifth place the pin 10 microfarad capacitor, 10 (plus the conclusion 8) and between the fifth and the common wire - 10 nF (it is non-polar).
Speaker impedance 8 ohms connected between the first and third terminals of the chip.Do not connect it to any of the parties to the common wire, otherwise amplifier blows.Between each of its terminal and the common wire put on the serial chain, consisting of 4.7 ohm resistor and a capacitor 100 nF.
Check amplifier work.Set the volume to the minimum, apply to the input signal and a power line, respecting the polarity - voltage 5 V from a source with a current capacity of about 2 A, via a fuse, designed for the same current.Gently rotate the knob clockwise until you get the desired sound volume.To turn the amplifier in stereo, collect a second channel bridge and apply it from the same source.