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14W CLASS A AMPLIFIER USING 2N3055 ELECTRONIC DIAGRAM Why Class A ? Because , when biased to class A, the transistors are always turned on, always ready to respond instantaneously to an input signal. Class B and Class AB output stages require a microsecond or more to turn on. The Class A operation permits cleaner operation under the high-current slewing conditions that occur when transient audio signal are fed difficult loads. His amplifier is basically simple, as can be seen from the block diagram.

The supply receive from 220 /120/110 Volt AC , then lowered by the transformer . Then receives +20 Volts DC from rectifier / filter section. This applied to pin 11 and 12 of the IC uA723/LM723 , as well as to the collector of the 2N3055 series pass transistor. The output through R1 and R2, providing about 7 V with respect to ground at pin 4. The reference terminal at pin 6 is tied directly to pin 5 , the non inverting input of the error amplifier . For fine trimming the output voltage , a potentiometer can be installed between R1 and R2. A 100-pF capacitor from pin 13 to pin 4 furnishes gain compensation for the amplifier. Base drive to the 2N3055 pass transistor is furnishes by pin of the uA723. Since desired output of the supply is 1 Ampere, maximum current limit is set to 1,5 Ampere by resistor Rsc whose value is 0,422 Ohm. A 100uF electrolytic capacitor is used for ripple voltage reduction at the output. A 1 kOhm output resistor provides stability for the power supply under no - lo...

This is OCL 150 W mono audio amplifier circuit , with impedance 8 Ohms. The supply voltage using 25 volt DC with triple voltage + ,- ,ground. see below this circuit : Buffer amplifier use PNP transistor is A564 / A733 /A1013 and NPN use D400 / D438. Driver Amplifier use NPN transistor is TIP31 / TIP41 / D401, and PNP transistor use TIP32 / TIP42 / B546. For the transistor booster or end , here I use a 2 x 20355 and MJ2955 . This anplifier is recomended to full range speakers. See pcb line and construction audio amplifier below : Click to view larger PCB line Components are already installed The booster amplifier already installed.

This is OCL 150 W mono audio amplifier circuit , with impedance 8 Ohms. The supply voltage using 25 volt DC with triple voltage + ,- ,ground. see below this circuit : Buffer amplifier use PNP transistor is A564 / A733 /A1013 and NPN use D400 / D438. Driver Amplifier use NPN transistor is TIP31 / TIP41 / D401, and PNP transistor use TIP32 / TIP42 / B546. For the transistor booster or end , here I use a 2 x 20355 and MJ2955 . This anplifier is recomended to full range speakers. See pcb line and construction audio amplifier below : Click to view larger PCB line Components are already installed The booster amplifier already installed.