A TIP41 power transistor is used in class A mode. The main function of the driver stage is to offer a high impedance i/p to the power amplifier. Select 1N4007, then the largest value of bias resistor is necessary for a low bias current, select resistor R9 which is equal to 3K. The selected biasing diodes properties are equal to the Darlington transistors. The power amplifier is designed with Darlington transistors such as TIP147 & TIP142 in the mode of class AB.
The capacitive reactance of C4 must be below the emitter resistance, the value of C4 is equal to 1uF. The value of R7 resistor is calculated from the values of resistor R5 and gain & found to be equal to 300 ohms, then the resistor R6 value is equal to 3.2 K. Here, resistor R7 is used as a feedback resistor to decrease the decoupling effect of C4. The emitter resistor value is 3.6 K (Ve/ Ie) and it is common between two resistors R6 &R7.
Resistors R3, R4 values are calculated by using the following equations.īy substituting the above values we get the R3 value, which is 130K & R4 value is equal to 22K.
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