Amplifier based on LM386

Another option for a simple, low-power, but very useful amplifier, which is based on the LM386 chip. Its maximum output power is 0.5 watts, which is quite enough to cover a small room. The advantages of the amplifier on this chip also include low power consumption, because in idle mode it consumes only 4 mA.

However, you cannot expect high sound quality from such an amplifier, because it is designed, first of all, for minimal cost and efficiency. Thus, this amplifier is ideal for voicing, for example, a doorbell signal. If desired, it can also be used in computer speakers or portable audio systems where low power consumption is important.

Amplifier circuit using LM386

In addition to the microcircuit itself, the circuit contains several resistors and capacitors. Connector CN1 in the diagram is used to connect power, CN2 is for a signal source, and a speaker is connected through CN3. PR1 is a variable resistor that controls the volume. The supply voltage of the circuit is in the range of 4-12 volts, the higher the voltage, the higher the output power. There is no need to greatly increase the supply voltage, becauseThe microcircuit does not provide for attachment to a radiator and may overheat. The optimal voltage is 9 volts. Light-emitting diode D1 lights up when power is applied to the amplifier.

Making an amplifier

As always, we start with the printed circuit board. It has dimensions of 65x25 and is performed using the LUT method; a printable file is attached to the article.

A few photos of the process:

Once all the copper is etched, the holes are drilled, and the traces are tinned, the parts can be soldered. First, small parts are installed - resistors, then everything else. Lastly, a variable resistor is soldered in. The board has a slot for a jack 3.5 connector; it is very convenient to use it to connect a player or phone to the board using an AUX cable. To connect power and speakers, the board also provides space for screw terminals. It should be noted that this amplifier is monophonic, i.e. provides for connecting only one speaker. To reproduce a stereo signal, you need to collect a second one of the same type.

Download the board:

Happy building!