Circuit Wiring

This is just addition 20W audio amplifier circuit , but this time based on the LM1875 audio amplifier IC from National Semiconductors. With a 25V bifold ability accumulation LM1875 can bear 20W of audio ability into a 4 ohm speaker. The LM1875 requires actual beneath external components and has actual low distortion.

The IC is aswell arranged with a lot acceptable appearance like fast bulk rate, advanced accumulation voltage range, top achievement current, top achievement voltage swing, thermal aegis etc. The IC is accessible in TO-220 artificial ability amalgamation and is able-bodied acceptable for a array of applications like audio systems, servo amplifiers, home theatre systems etc.

Notes.

• Assemble the circuit on a good quality PCB.
• Use +/-25V DC dual supply for powering the circuit.
• K1 can be 4 ohm, 20W speaker.
• A proper heat sink is necessary for the IC.
• F1 and F2 are 2A

This Fm rf power amplifier has 2 transistors from Philips : BLV 10 and BLW 87. The 2 rf transistors work in class C and this fm amplifier has a total gain of 21dB ( 100 X ) and efficiency 55 – 65%.
One low pass filter with 9 components ensures 60dB rejection on the second harmonic. There is no need for tune-up to cover the whole 88 – 108 MHz FM frequencies.


source [link] 

Have you been use the IC above? if those who have not, IC above is used or applied to the audio power amplifier. IC processing is quite good for use on amplifier home, or room. IC used is SI1020G who have not very high output with only 20W 8 ohm impedance speakers. Supply voltage ranging from 12 volt to 23 volts.

Below schematic audio amplifier with IC SI1020G

Part List

R1 = 100K

R2 = 1R

C1 = 2u2F

C2 = 100uF
C3 = 47uF

C4 = 10uF
C5 = 2200uF
C6 = 47uF

C7 = 100uF