Audio Amplifier using LM386

Audio amplifier - LM386

LM386 is a power amplifier designed to be used in low voltage consumer applications. Typical applications are like portable AM/FM amplifier, TV sound systems. It requires minimum external parts and operate from wide range of voltage starting from as low as 4 volt.

Below is the version of the circuit designed by me in one of my projects. It has a Gain of 50 with Bass boost.

Part list

1. C1 - 100 µf 

2. C2 - 10 µf

3. C3 - 0.01 µf

4. C4 - 0.1 µf

5. C5 - 0.01 µf

6. C6 - 220 µf

7. R1 - 10 K

8. R2 - 1.2 K

9. R3 - 10 

10. VR1 - 10 K

11. 9 volt Battery

12. IC - LM386 

C3 and C4 can be replaced by 0.05 or 0.047 µf capacitor. 

This amplifier is ideal for Ipod and cell phones and can be assembled in small box. 

White LED on 1.5 v Supply

2 White LED on 1.5 v Supply

Parts

T1 - BC338

R1 - 2.7 K

C1 - 10 n

D1,D2 - Super bright LED

Transformer - 60 T, 40 T

S1 - On/off Switch

Battery 1.5 V

White LED Flasher

Parts

T1 - BC338

T2 - 2N2222

R1 - 2.7 K

R2 - 47 R

R3 - 330 R - 1K

C1 - 10 n

C2 - 100 

D2 - 1N4148

Battery 1.5 v

1 Watt Audio Amplifier

Audio Amplifier

Parts

Q1 Transistor - MPSW45A
R1- 50 ohms
R2- 10 K
R3,R4 - 100 K

9 volt battery and Speaker

Flashing LED

Alternate red and green flashing LED using 9 volt battery



Part list 

1. R1,R2 - 100 Ohm
2. R3,R4 - 105 K
3. C1,C2 - 10 μF 25 Volt
4. T1-T2 - BC 548
5. D1-D5 - Red LED
6. D6-D10 - Green LED
7. 9 Volt Battery
 

Dark Sensor

Dark sensor using 2 transistor BC547

When light falls on LDR, its low resistance drives the transistor T1 into conduction. This keeps transistor T2 cut-off due to low base bias. The LED does not get power as long  as ambient light falls on it.

Parts list

1. T1 and T2 - BC 547
2. LDR  -1 nos
3. Resistance  R1 - 1k
4. R2 & R3 - 330 Ohms
5. 6 volt battery

Modifying the above circuit to use with Relay and switch on / off

You can also modify the above circuit in controlling AC appliances. Remove R2 and LED from the circuit and also remove the positive connection to Pole of the relay. Connect the AC bulb or any other appliance as shown



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