50W后级放大电路图

georgedl

国外网站上的，原文复制过来了，懂英文的朋友翻译一下吧，很一般的电路，大家随便看看。


This simple audio power amplifier was originally designed for a circuit board workshop, conducted by the OSU IEEE Student Group. At the workshop, 20 participants each constructed this amplifier, by etching and drilling the single sided circuit board, soldering all components, and attaching a pre-built heatsink assembly with the output transistors. Three workshops were held between 1995 to 1996. Though the design is simple, these amplifiers have impressive performance, with a frequency response to approx 40 kHz, very low noise, reasonably fast slew rate, and approx 50 watts (true "RMS" power) with the proper +/- 40 volt unregulated power supply.

Note: The TIP33C and TIP34C have been discontinued and are generally not available anywhere. I replace the Q11=TIP33C and Q12=TIP34C with BD249C and BD250C
Testing

If any of these tests fail, the amp is not constructed properly... the easiest and best way to find the problem is visual inspection.

    Turn variable resistor fully counter clockwise (max resistance)
    Connect to +/- 24 volt supply with 200mA current limit. No input and no output connected. Monitor current from power supply with a current meter.
    Apply power... if current is above about 25 mA, shut off immediately!
    Measure voltage across the 1k resistor connected to the input stage and Vcc. The DC voltage should be about 2 volt, or 2 mA of current through this resistor. Eg, if +V is at 24 volts, the side of this resistor connected to the BC550C transistor ought to be at about 22 volts.
    Measure the DC voltage on the output line. It should be appox zero volts. +/-0.05 volts is probably fine.
    Turn the variable resistor slowly until the amplifier’s current consumption is approx 50 mA. Turn slowly and be careful... if you turn too far you could damage the output transistors.
    Connect an oscilloscope to the output and apply a low amplitude 20 kHz square wave to the input. DO NOT connect any speakers during this test. This test should be done without the C1=330pF capacitor installed. The amp should output a 20 kHz square wave with very little "ringing". It should not oscillate.
    Solder the C1 capacitor into the circuit.
    Shut off the power, connect audio input and a speaker. Make sure the volume is turned all the way down. Apply power... watch current meter again and shut off the power immediately if the current jumps to something much higher than 50 mA.
    .Slowly turn up the volume and see if the amp works. DO NOT turn it up very much... the amplifier should not be operated with a supply less than +/- 30 volts. It should never be used for high volume output without a power supply rated for at least 2 amps of current (8 ohm load). After this initial test with +/- 24V at 200 mA (current limited) only a proper power supply should be used which can provide enough current.

Source:[PJRC]
       

Part List
       
R1=4.7 ohm 1/4W         R23-25=0.33 ohm / 4W         Q8=BD240C [on small Heatsink]
R2-16=47 Kohm 1/4W         TR1=5 Kohm Top adjust cermet trim pot         Q10=2N3906
R3=10 Kohm 1/4W         C1=330pF NPO Capacitor         Q11=BD249C [on Heatsink]
R4-5=47 ohm 1/4W         C2-3-6-7-12-13=100nF 100V MKT         Q12=BD250C [on Heatsink]
R6=3.3 Kohm 1/4W         C4-5-8-14=100uF 63V         D1-2=12V 0.5W ZENER
R7-8=2.2 Kohm 0.5W         C9=47pF NPO Capacitor         D3-4-5=1N4002
R9-15=1 Kohm 1/4W         C10-11=100uF 16V         D6-7-8-9-10=1N4148
R10=6.8 Kohm 1/4W         Q1-2-3=BC550C         J1=3pin connector with 2.54mm step
R11-17=1.1 Kohm 1/4W         Q4=MPSA56         J2=5pin connector with screws
R12-18-19-20-21-22=220 ohm 1/4W         Q5-9=2N3904         F1-2=Fuse2A Fast
R13=330 ohm  1/4W         Q6=MPSA06        
R14=22 Kohm 1/4W         Q7=BD239C [on small Heatsink]
电源部分
TR1=220VAC/2X28V  6A         C1=33nF 630V         C9-10=15000uF 63V
F1=Fuse 1A Slow         C2-3=22nF 100V  MKT         C8-11=100nF 100V  MKT
S1=2X10A SW         C4-5=22nF 100V  MKT         D1-4= rectifier bridge  400V 35A
JF1=3P Connector 3.96mm step         C6-7=15000uF 63V

yamamoto

回复 2# 大侠就等待


    由一个二十人的团队，参加了这个电路的设计
就这破电路还要20人去设计？

想学维修

95～96年

程胜

没看懂，看来我还要在坛子里跟大侠们好好学习。

kensonkong

这个图不是一般的复杂呢。。坐等大虾

yamamoto

回复 6# 大侠就等待

georgedl

楼主在吗
大侠就等待 发表于 2013-1-30 09:38

    何事？发信息。

georgedl

回复 3# 大侠就等待


    没有PCB，在谷歌网站找到的，现在才发现与谷歌比较百度真的不行。

yue2013

这个电路就是一个经典电路之一，都没有变形，只不过又加进了一些辅助的器件，貌似复杂，精简一下就得看了。