Showing posts with label 15. Show all posts
Showing posts with label 15. Show all posts

Tuesday, September 23, 2014

Audio Power Amplifier 15 Watt

Audio Power Amplifier 15 Watt

15

This amplifier uses a dual 20 Volt power supply and delivers 15 watts RMS into an 8 ohm load. Q1 operates in common emitter, the input signal being passed to the bias chain consisting of Q8, Q9, D6, D13 and D14. Q8 and Q9 provide a constant current through the bias chain to minimize distortion, the output stage formed by a discrete darlington pair (Q2,Q4) and (Q7,Q11).

The last two transistors are power Transitors, specifically the 2N3055 and MJ2955. The 7.02K resistor, R16 was made using a series combination of a 4.7K, 680 Ohms, and two 820 Ohms. The 1.1K resistor, R3 was made using a 100 Ohms and a 1K resistor. You can use this circuit with any walkman or CD player since it is designed to take a standard 500mv RMS signal.

This amplifier uses a dual 20 Volt power supply and delivers 15 watts RMS into an 8 ohm load. Q1 operates in common emitter, the input signal being passed to the bias chain consisting of Q8, Q9, D6, D13 and D14. Q8 and Q9 provide a constant current through the bias chain to minimize distortion, the output stage formed by a discrete darlington pair (Q2, Q4) and (Q7, Q11). The last two transistors are power Transitors, specifically the 2N3055 and MJ2955. The 7.02K resistor, R16 was made using a series combination of a 4.7K, 680 Ohms, and two 820 Ohms. The 1.1K resistor, R3 was made using a 100 Ohms and a 1K resistor.

You can use 15 Watt Audio Power Amplifier circuit with any walkman or CD player since it is designed to take a standard 500mv RMS signal.
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Saturday, August 30, 2014

15 V output regulated power supply circuit with uA723 and 2N3055

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 - load conditions. The 2N3055 pass transistor must be mounted on an adequate heatsink.
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