If the speaker system does not have a built-in amplifier, it must be located outside. This amplifier can be home-made, made on the basis of specialized microcircuits.
Instructions
Step 1
The disadvantage of a 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 push-pull, operating in antiphase. The speaker is connected between their outputs. To build such an amplifier, purchase a TDA2822 type microcircuit. Solder its power pins first: the second to the positive rail, and the fourth and sixth to the common wire. Between the positive bus and the common wire, install, observing the polarity, an electrolytic capacitor with a capacity of 1000 μF, designed for a voltage of at least 16 V. In parallel, connect a ceramic or paper capacitor of any capacity.
Step 2
Assemble the amplifier's input circuit. To do this, take a variable resistor with a type B characteristic, having a resistance of about 100 kilo-ohms. Place it with the leads facing you, with the handle facing up. Connect the left terminal to the common wire, the middle one to the central contact of the input socket, and from the right, remove the signal to be fed to the amplifier through a capacitor with a capacity of 10 μF, designed for a voltage of at least 10 V (with a negative plate to the regulator). Connect the positive plate of this capacitor to the seventh pin of the microcircuit, and the body of the input socket with the common wire of the amplifier. Also, between the seventh pin of the microcircuit and the common wire, turn on a 10 kilo-ohm resistor.
Step 3
Assemble the adjustment chain. To do this, place a 10 microfarad, 10 V capacitor between the eighth and fifth pins (plus to pin 8), and between the fifth and common wire - 10 nanofarads (it is non-polar).
Step 4
Connect a speaker with an impedance of 8 ohms between the first and third pins of the microcircuit. Do not connect it on either side with a common wire, otherwise the amplifier will burn out. Between each of its terminals and the common wire, place it in a series circuit consisting of a 4.7 ohm resistor and a 100 nanofarad capacitor.
Step 5
Check the amplifier in operation. Set the volume control to the minimum position, apply a signal to the input, and to the power bus, observing the polarity, a voltage of 5 V from a source rated for a current of about 2 A through a fuse rated for the same current. Smoothly rotating the knob clockwise to achieve the desired sound volume. To turn your amplifier into stereo, collect a second channel and power it from the same source.
