Circuit audio power amplifier circuit IC LM386 PCB include

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• AM-FM radio amplifiers
• Portable tape player amplifiers
• Intercoms
• TV sound systems
• Line drivers
• Ultrasonic drivers
• Small servo drivers
• Power converters

Equivalent Schematic and Connection Diagrams  LM386M-1, LM386MM-1, LM386N-1, LM386N-3 or LM386N-4

Application Hints

GAIN CONTROL
To make the LM386 a more versatile amplifier, two pins (1and 8) are provided for gain control. With pins 1 and 8 open the 1.35 kΩ resistor sets the gain at 20 (26 dB). If a capacitor is put from pin 1 to 8, bypassing the 1.35 kΩ resistor, the gain will go up to 200 (46 dB). If a resistor is placed in series with the capacitor, the gain can be set to any value from 20to 200. Gain control can also be done by capacitively coupling a resistor (or FET) from pin 1 to ground.Additional  external  components  can  be  placed  in  parallel with the internal feedback resistors to tailor the gain and frequency  response  for  individual  applications.  For  example, we  can  compensate  poor  speaker  bass  response  by  frequency shaping the feedback path. This is done with a series RC from pin 1 to 5 (paralleling the internal 15kΩ resistor). For 6 dB effective bass boost: R. 15 kΩ, the lowest value for good stable operation is R = 10 kΩ if pin 8 is open. If pins1 and 8 are bypassed then R as low as 2kΩ can be used. This restriction is because the amplifier is only compensated for closed-loop gains greater than 9.

Schematic of power audio amplifier for applications as Amplifiers of radio FM, Amplifiers of mp3 portable players, Intercoms, Systems of sound of TV and other applications.

Schematic circuit amp using lm386

The power supply for this circuit should be 3 to 12 volts.

Suggestion of printed circuit board

Part List for the LM386 Amp

Component	Value
Resistors 1/4W 5%
R1	10 – Brown, Black, Black, Gold
R2	1.2k – Brown, Red, Red, Gold
R3	4.7K – Yellow, Violet, Red, Gold
R4	1.5K – Brown, Green, Red, Gold
Capacitors
C1, C6	10µF/16V – Capacitor electrolytic
C2	220µF/16V – Capacitor electrolytic
C3	100n – Ceramic or polyester capacitor
C4	1000µF/16V – Capacitor electrolytic
C5	100n – Capacitor ceramic
Semiconductor
IC1	LM386
LED1	Red Led 5mm
Connectors
J1	P2 connector – audio input
J4	Jack Connector – DC Power
J5	Audio input connector (optional)
J6	Power connector (Optional)
JP1	Jumper gain adjustment (optional)
OUT	Terminal block connector 2 screws – Audio output
Miscellaneous
P1	Single potentiometer 4.7K
3 to 12V / 1A power supply
Printed circuit board, solder, wires, box, knob, etc.

Download PDF files for Lm386 amplifier
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