BA5417 Stereo Power Amplifier Circuit

BA5417 stereo amplifier circuit has of good features like thermal shut down, standby function, soft clipping, wide operating voltage range etc. The circuit can be deliver 5W × 2 when VCC = 12V and RL = 4Ω, or 2.8W x 2 when VCC = 9V RL = 3Ω.This and amplifier circuit has excellent sound quality, and low THD (total harmonic distortion) around 0.1% at F = 1kHz; Pout = 0.5W

BA5417 Stereo Power Amplifier Circuit

C-in are DC decoupling capacitors which block any DC level present in the input signals. C3 and C5 couples the amplifiers left and right power outputs to the corresponding loud speakers. C2 and C6 are bootstrap capacitors. Bootstrapping is a method in which a portion of the amplifiers is taken and applied to the input. The prime objective of bootstrapping is to improve the input impedance. Networks R1,C1 and R2,C7 are meant for improving the high frequency stability of the circuit. C4 is the power supply filter capacitor. S1 is the standby switch. C8 is a filter capacitor. RF1 and RF2 sets the gain of the left and right channels of the amplifier in conjunction with the 39K internal feedback resistors.

3VDC Stereo Headphone Amplifier by IC LM4910

This is a stereo headphone amplifier circuit of using LM4910 IC. This circuit is very simple so it is very easy to make even for beginners once. because the voltage source is used only 3 VDC you can use 2 x A3 battery in series stacking.

 

Circuit diagram of 3VDC Stereo Headphone 

Amplifier by LM4910 

IC LM4910 Pinout

LM4910 Boomer belonging to the series of National Semiconductors is an integrated stereo amplifier is primarily intended for headphone stereo applications. The IC can be operated from 3.3V ans its 0.35mW can deliver output power into a 32 ohm load. The LM4910 has very low distortion (less than 1%) and the shutdown current is less than 1uA. This low shutdown current makes it Suitable for battery operated applications.

C1 and C2 are the input DC decoupling capacitors for the left and right input channels. R1 and R2 are the respective input resistors. R3 is the feed back resistor for left channel while R4 is the feed back resistor for the right channel. C3 is the power supply filter capacitor. The feedback resistors also sets the closed loop gain in conjunction with the corresponding input resistors.

10 LED VU Meter Using IC LM3914

This 10 LED VU meter circuit has only a few parts but is useful as an indicator for the measurement of entering acoustic signals. The circuit is a perfect one chip replacement for the standard analog meters. It is completely solid state and will never wear out

LM3914 VU Meter Circuit

The circuit is built around an LM3914 IC. The input signal from the VU meter is put on pin 5 of IC1. Through pin 9 of IC1 is the display mode sets (bar or dot instructions). In the drawn state IC1 works in the dot mode. When pin 9 is coupled to pin 3, the IC works in bar mode. Obviously the whole circuit consumes less power in dot mode.

List Component

C1        : 2.2uF/ 25V Electrolytic Capacitor
R1        : 1K  Resistor
D1        : 1N4002 Diode
LED1-LED  : 10 x  LED or LED Array
U1        : LM3915 

Notes

• V+ can be anywhere from 3V to 20V. 
• The input is designed for standard audio line voltage with has a maximum input voltage of 1.3V.
• Pin 9 can be disconnected from ground to make the circuit use a moving dot display instead of a bar graph display.