Discrete Class 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,Q4andQ2,Q5arecomplementarypairs,theymakecomplementarydarlington pairs.
|Q6, Q7, Q8, Q9, Q10||2SA733|
|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|
10W is much enough for the day today home usage.
Amplification of this amplifier (A)
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.