AB Transistor Audio Power Amplifier Circuit Diagram

This is a class AB transistor power amplifier. It is a simple amplifier to build, uses standard parts and is stable and reliable. The entire circuit utilizes commonly available components and may be simply built over a general-purpose board. But this amplifier has very good sound quality.

There are eleven transistors, including four in the output stage. Q1 and Q2 transistor must be between 3 and 5 amperes power transistors. Q4 and Q5 must be between 100mA and 500mA driver transistors. Other transistors are 10mA small driver transistors. Q1, Q4 and Q2, Q5 are complementary pairs, they make complementary darlington pairs.

PART LIST
R1	1.5KΩ ¼W
R2	150Ω ¼W
R3	1KΩ ¼W
R4	0.22Ω 2W
R5	0.22Ω 2W
R6	39KΩ ¼W
R7	1KΩ ¼W
R8	120Ω ¼W
R9	6.8KΩ ¼W
R10	6.8KΩ ¼W
R11	47KΩ ¼W
R12	47KΩ ¼W
R13	2.2KΩ ¼W
R14	180KΩ ¼W
R15	18KΩ ¼W
C1	22pF Ceramic
C2	4.7µF 16V
C3	1000µF 25V
C4	100µF 25V
D1	1N4148
D2	1N4148
Q1	2SD313
Q2	2SB507
Q3	2SA733
Q4	2SB560
Q5	2SD400
Q6, Q7, Q8, Q9, Q10	2SA733
Q11	2SD400
LS1	4Ω 20W SPEAKER

Power output of the amplifier

Supply voltage (Vs)	= 20V
Speaker impedance (R)	= 4Ω
Peak to peak voltage (Vpp)	= 20-2 =18V
Peak voltage	= 9V
Maximum output (Pmax)	= 9V²/2R
	= 81/8
	= 10W

10W is much enough for the day today home usage.
Amplification of this amplifier (A)

A	= R6/R13+1
	= 39KΩ/2.2KΩ+1
	= 18

Volume control can be added to the circuit by connecting a 10KΩ POT in series to the input of the amplifier.

Q1 and Q2 must be kept sufficiently cool, so it is mounted on a suitable heat sink. If you used single heat sink please use insulation between transistors and heat sink.

Comments

3 Channels Audio Splitter Amplifier Circuit Diagram using TL084

This is the schematic diagram of 3 channels audio splitter amplifier circuit which built using op-amp IC TL084. The 3 channels amplifier output distribution applies a single TL084. 3 Channels Audio Splitter Amplifier Circuit Diagram The very first step is to capacitive coupling having a p. 1.0 ~ electrolytic capacitor. The entries are railways Vee Y2 or 4.5 V. This enables working with an individual 9V power source. A voltage gain of 10 (1 M?/100 Kohm) is obtained in the first stage, as well as the other three floors are connected as a unity gain voltage followers. Every single output stage drives independently through an amplifier output 50 pF capacitor towards the resistance of 5.1 k ohm load. The response range is flat from 10 Hz to 30 kHz.

Simple But Automatic Load Sensing Power Switch

This circuit will automatically switch on several mains-powered "slave" loads when a "master" load is turned on. For example, it will switch on the amplifier and CD player in a stereo system when the receiver is turned on. It works by sensing the current draw of the "master" device through a low value high wattage resistor using a comparator. The output of that comparator then switches on the "slave" relay. The circuit can be built into a power bar, extension cord or power center to provide a convenient set of "smart" outlets that switch on when the master appliance is powered (turn on the computer monitor and the computer, printer and other peripherals come on as well). Automatic Load Sensing Power Switch Circuit Diagram Parts List: Notes: This circuit is designed for 120V operation. For 240V operation, resistors R2 and R6 will need to be changed. A maximum of 5A can be used as the master unless the wattage of R1 is increased S1 provid...

RF amplifier protection

RF amplifier protection I have developed the protection circuit for the EB104 amplifier I am working on, after I finally had some time to design and test a few models. The main requirements have been: - protection in case of high temperature; - protection in case of high SWR; - protection in case of wrong output filter selection; - simple design (i’m a fan of the whole K.I.S.S. rule of thought), able to work in strong electromagnetic fields, reliable, inexpensive. Because i will be using the same directional coupler i have used in the SWR meter (the one made on PCB) wich is directly influenced by the signal frequency, and because i want full HF coverage, i cannot just measure the reflected signal and make a circuit cut the amplifier when it goes over a limit; on 28Mhz the coupler generates roughly 4 times more voltage that let’s say in 7Mhz. So a system that compares direct and reflected signal and triggers when the latter is percentually too high was needed, therefore an operational a...

TREE

Search This Blog