Here is one another circuit in the series of audio power amplifier. Previously we had already posted 3W and 20W audio amplifier using transistor. Now we use integrated circuit instead of transistor for designing audio amplifier circuit. By using IC TBA810 one can get power output of 7W.
The audio power amplifier featuring the TBA810 integrated circuit is shown in figure 1. This IC incorporated build-in-terminal shutdown, which automatically reduces the output in the event of sustained overloads or if the heat sinking arrangement are inadequate. We use few passive components like resistors and capacitors to build this audio amplifier.
The input impedance of the IC TBA810 (IC1) is very high about 5MΩ. The impedance of the circuit 7W audio amplifier using TBA810 is determined by resistor R1 and sensitivity is determined by resistor R2. The input sensitivity of the circuit is 65Mv with the value of resistor R2 = 47Ω.
Capacitor C2 should be fairly large to ensure a good low-frequency response. Capacitor C3 decouples the supply to the earlier stage of the IC. This decoupling reduces noise in the preamplifier stage of the IC and also eliminates output-input coupling through the power supply. Additional RC feedback network may be inserted to boost low frequency to compensate for a poor speaker bass response.
PARTS LIST OF 7W AUDIO AMPLIFIER USING TBA810
|Resistor (all ¼-watt, ± 5% Carbon)|
|R1 = 47 KΩR2 = 47 ΩR3 = 100 Ω
R4 = 1 Ω
|C1 = 10 µF/12VC2 = 250 µF/6VC3 = 100 µF/12V
C4 = 4.7kpF
C5 = 100 µF/16V
C6 = 1.5kpF
C7, C10 = 0.1 µF
C8 = 1000 µF/16V
C9 = 100 µF/25V
|IC1 = TBA810|
|LS1 = 4 Ω loud speaker|