Audio Amplifier LM386

Audio Amplifiers with LM386




The LM386 is a versatile, small power amplifier designed for use in low voltage consumer applications. The gain is internally set to 20 to keep external part count low, but with the addition of an external resistor and capacitor between pins 1-8 the gain can be set to any value from 20 to 200.

The inputs are ground referenced and the output automatically biases to one-half the supply voltage. The quiescent power drain is only 24 milliwatts when operating from a 6 Volt supply, making the LM386 ideal for battery operation.



To make the LM 386 a more versatile amplifier, 2 pins (pin 1 and 8) are provided for gain control. With pins 1 and 8 open the internal 1.35k resistor sets the gain at 20 (26 dB). If a capacitor is placed between pin 1-8, bypassing the built-in 1.35k resistor, the gain will go up to 200.

If a resistor is placed in series with the capacitor, the gain can be set to any value from 20 to 200. Gain control can also be done by capacitively coupling a resistor or FET transistor from pin 1 to the ground.

Simple audio amplifier schematics with LM386

• Operating Supply Voltage (VS) = 4v - 12v 
• The output power (POUT) for LM386N-1, LM386M-1 at VS = 6V, RL = 8ohms, 
• THD = 10% is 250-325 mW for LM386N-3 at VS = 9V, RL = 8ohms, 
• THD = 10% is 500-700 mW for LM386N-4 at VS = 16V, RL = 32ohms, 
• THD = 10% is 700-1000 mW. 

Fig 1: LM386 Audio Amplifier with Gain = 20 and minimum part count


Fig 1: LM386 Audio Amplifier with Gain = 200


Fig 1: Audio Amplifier with bass boost

200W Subwoofer Amplifier Circuit

Circuit Description

Here is a circuit that uses a mosfet amplifier amplicable for subwoofer as the main booster, or the basis of this boosterAmplifier. Circuit which uses MOSFET Power Amplifier is powered by the output more than 200W Speaker 8 Ohm impedance. We also include a suitable power supply circuit with the use of MOSFETamplifier with 200W of power, not only of his course Schematic diagram for the layout design is also already there.

Amplifier Circuit Diagram

Amplifier Circuit Diagram

200W Mosfet Amplifier LAyout PCB

200W Mosfet Amplifier LAyout PCB

Regulator Circuit Diagram MOSFET AMPLIFIER

Regulator Circuit Diagram MOSFET AMPLIFIER

Regulator PCB MOSFET amplifier

Regulator PCB MOSFET amplifier

Amplifier Circuit Diagram

Description:

I have been looking for a good stereo amplifier circuit diagram for a long time. I am not a HiFi geek, I just wanted to build a simple stereo amplifier that could drive some speakers for my desktop computer.

All the schematic diagrams that I could find seemed to involve lots of hard-to-find components or you had to use it together with a pre-amplifier or some other amplifier stage. It was always something that made me hesitate. But recently I found this awesome little chip called TEA2025! You only need a few capacitors to make a decent stereo amplifier out of it. It is so simple to build that I put it together on a strip board in just a few hours. The amplifier circuit diagram shows a 2.5W * 2 stereo amplifier. You can also make a 5W mono amplifier out of it. On the input side, you should use a dual potentiometer. A dual potmeter allows you to connect both left and right channel on one potentiometer. This amplifier is great to use together with some speakers to get sound on your desktop computer. I am thinking of putting one in my kitchen and in my bathroom also. Then maybe hook them up to my home network and stream music from a server =) There are many possibilities when you can make such a cheap amplifier.

Amplifier circuit diagram:

Amplifier circuit diagram

Subwoofer Amplifier Circuit Diagram 300w

This is basic amplifier schematic, 

Small transistor amplifier Ideals

Currently, ICs has been used in many audio amplifiers,especially small circuit. It is convenient to use transistors.But when you need to use transistors, it has several advantages, such as saving you can take old equipment come to made small circuits easier than the IC. Which may be difficult to find. Take a look at these circuits. Maybe you get the idea of it.

Low impedance mini amplifier

This circuit can apply to signal sound source that has low impedance , such as from 4-16 ohm size loudspeakers or telephone earphone that use to replace , Micro phone. If use a loudspeaker replaces the rapidity will enough in sound checking that has been born from walking. The output this can feed reach input of high power amplifier the other next.


Power Amplifier OTL by AC176+AC126


Mr Somsak is my friend who like to make power amplifier so much. but he do not well electronic man. I so introduce he need make easy project before. This circuit is simple power amplifier OTL that mini watt output but is older circuit.

They uses transistors example number are AC176 , AC126 and BC109. which there has other a few components. They are used power Supply Voltage 9Volt only. I hope it will be once circuit so you like and well ideas.


Power Amplifier OTL Cassette Radio Booster by TIP41+TIP42




This is mini Power Amplifier OTL for Cassette Radio Booster. it have transistor TIP41 + circuits of TIP42 Drive speaker sound. Volt supply see in image.

Simple Amplifier by Transistor AC128

I find this in my old circuit electronics book. It is very a small power amplifier, but good quality audio class AB amplifier in hi-fi applications. The component capable of delivering 2W continuously an used the AC128 thansistor into a 8 ohm load and 5W peak. with the proper 9 volt unregulated power supply.

Original article sourse eleccircuit.com.

Amplifier power supply using High Current Transformer

Circuit Description    

    Friends ever meet a problem power supply Circuit give current not enough. I has way this out give friends try apply. Follow this circuit High Current transformer parallel circuit make you have Current tall go up very. The transformer that have many the coil , we can bring to do high Current power supply circuit well. By if the all coil has Voltage be equal. It is can bring parallel can follow this circuit is coil lead that has Voltage 24V and have Current about 1A come to parallel prevent all 2 the group have current altogether each 2A groups by have voltage at 24V be the same. This circuit then can become Dual power supply at 34V positive and -34V Negative and Ground. This circuit uses to are amplifier power supply get good. Suppose will give the electric power about 50watt. For the diode use 3A 100V sizes and use. The Stancor for filter noise signal the all well. This circuit may help to give testimony have the idea in applying work other , get please sir.

Original article sourse elecfree.com

Amplifier circuit diagram

100W subwoofer amplifier

General Description:

     This is the circuit diagram of a fully transistorized sub woofer amplifier that can produce an output of 100W.There are seven transistors including four in the output stage. The transistors Q1 and Q2 form the preamplifier stage. Transistors Q4 to Q7 form the output stage. Since no ICs are used the circuit is very robust and can be easily assembled on a general purpose PCB.

Circuits features:

• The circuit can be powered from a +35V/-35V, 5A dual power supply.
• Use a 100W, 12 inch sub woofer at the output.
• All electrolytic capacitors must be rated 100V.
• The transistor Q4 to Q7 must be fitted with heat sinks.

Circuit Diagram:

100W subwoofer amplifier circuit