electronics-amplifier tutorial

This is a 60W power amplifier circuit based on 2N3055 transistor. The optimal supply voltage is around 50V, but this amp can work from 30 to 60V. As you can see, in this design the components have a big tolerance, so you can build it with almost any components that you can find at home. The output power transistors can be any NPN types, but do not use Darlington types.

Capacitor C1 regulates the low frequencies (bass), as the capacitance grows, the low frequencies are getting louder. Capacitor C2 regulates the higher frequencies (treble), as the capacitance grows, the higher frequencies are getting quieter.

This is a class B amplifier, this means, that a current must flow through the end transistors, even if there is no signal on the input. This current can be regulated with the 500 Ohm trimmer resistor. As this current increases, the sound of the amplifier is better, but output transistors are dispatching more heat. If the current is decreased, the transistors are dispatching less heat, but the sound quality is decreased.

This is a 300W power amplifier OCL circuit that the circuit has been stout kit on the market. If you are fanatical about the use of transistors 2N3055 and MJ2955 jengkol then this circuit is the answer. This power amplifier OCL circuit delivering a blasting 300 watts to a 4 Ohm speaker.

The amplifier circuit is very Cheapest and cans be powered from 24 to 32 V/5A dual power supply. You must try this circuit. Its working great. Because 4 transistors (2 x 2n3055 and mj 2955) on the final amplifier will of some very hot then add the aluminum finned cooler and the fan so That the transistor is not too high temperatures

The TDA7293 Power Amplifier circuit is conventional, and is very simple because all additional internal functions are unused. The LED is optional, and if you don't think you'll need it, it may be omitted, along with series resistor R3. All connections can be made with plugs and sockets, or hard wired. In most cases, I expect that hard wiring will be the most common, as the connectors are a pain to wire, and add unnecessary cost as well as reduce reliability.

The TDA7293 amplifier specifications might lead you to believe that it can use supply voltages of up to ±50V. With zero input signal (and therefore no output) it might, but I don't recommend anything greater than ±35V if 4 ohm loads are expected, although ±42V will be fine if you can provide good heatsinking. In general, the lower supply voltage is more than acceptable for 99% of all applications, and higher voltages should not be used unless there is no choice. Naturally, if you can afford to lose a few ICs to experiments, then go for the 42V supplies (obtained from a 30+30V transformer).

This is a circuit of 60 watt HiFi audio amplifier system using IC TDA2052 . The circuit is class AB amplifier which operates split power supply type with a maximum voltage of 25V and generates 60 Watt power output. Heatsink should be installed on the power IC to avoid excessive heat.

TDA2052 IC Pinning

The TDA2052 is a monolithic integrated circuit in Heptawatt package, intended for use as audio class AB amplifier in TV or Hi-Fi field application. Thanks to the wide voltage range and to the high out current capability it’s able to supply the highest power into both 4/8 loads even in presence of poor supply regulation. The built in Muting/Stand-by function simplifies the remote operations avoiding also switching on-off noises

DC Supply Voltage                         :  ±25 V
Output Peak Current (internally limited)  : 6 A
Power Dissipation                         : 70°C 30W
Operating Temperature Range               : +70 °C
Storage and Junction Temperature          : -40 to +150 °C

The following a circuit of 80W audio amplifier is using by IC TDA7295. The circuit very simple and will be easy to build. TDA7295 has many features to support your audio system, the most important is that the IC has wide voltage range, very low distortion and very low noise feature.

Rangkaian Audio Amplifier TDA7295 - 80W

TDA7295 IC Pinning

The TDA7295 is a monolithic integrated circuit in Multiwatt 15 package, intended for use as audio class AB amplifier in Hi-Fi field applications (Home Stereo, self powered loudspeakers, Topclass TV). Thanks to the wide voltage range and to the high out current capability it is able to supply the highest power into both 4Ω and 8Ω loads even in presence of poor supply regulation, with high Supply Voltage Rejection. The built in muting function with turn on delay simplifies the remote operation avoiding switching on-off noises.

This is a 2 x 70W audio power amplifier circuit which built using single IC STA550. The amplifier circuit require few external components (most of them are resistors and capacitors) and is very easy to design The STA550 audio amplifier is capable to provide a maximum output power of 70 watts on two channels (70 + 70 watts).

This power amplifier circuit require a multi voltage power supply , because the amplifier require : +Vs Positive supply voltage referred to pin 13 (GND), Negative supply voltage referred to pin 13 (GND) -Vs, VCD+ Positive supply voltage tracking rail, VCD- Negative supply voltage tracking rail . The +Vs Positive supply voltage can be : +20 to +30 volts, -Vs Negative supply voltage : -10 to -22 volts , Positive supply voltage tracking rail VCD+ : +3 to 17 volts , Negative supply voltage tracking rail VCD- : -17 to -3 volts . VCD- must not be more negative than -Vs and VCD+ must not be more positive than +VS .

In this circuit diagram, R1/R3 (or R2/R4) ratio fix the gain of the preamplifier. If the input signal is very low, is possible to increase the gain fixing the product Vin*G = cost. In that case is possible to increase G decreasing R1,2 from 10KW until 2KW without relevant effetcs on the circuit behavior and remaining in the operating range Iin_max = Vin_max/R1(2) <1ma.>This is a 2 x 70W audio power amplifier circuit which built using single IC STA550.

Rangkaian Amplifier TK4036II

This is a 50 Watt Audio power amplifier circuit based single IC STK4036II. Use heatsink to prevent overheating on the IC. The amplifier circuit will give you good quality of sound unexpensive and have low price. It is easy we make a power amplifier using only few external components. The STK4036II amplifier are will find in enough eponymous stereo amplifiers , but also in enough activety loudspeakers.

Rangkaian STK4036II - 50W Stereo Power Amplifier

Here is a 35 Watt audio amplifier circuit based LM391 chip. The LM391 Audio Power Driver is designed to drive external Power Transistors in 10 to 100 watt power Amplifier designs. High power supply voltage operation and true high fidelity performance distinguish this IC. The LM391 is internally pro- tected for output faults and thermal overloads; circuitry pro- viding output Transistor protection is user programmable. By National Semiconductor

Rangkaian 35 Watt Power Amplifier
Based on LM391

The circuit was designed to drive the power transistors of a power amplifier that will produce a power output of 35 Watts. Inductor L1 is constituted by 20 coils of wire, with thickness 0.9mm, round resistor R16. Transistors Q3-4 should be placed on heatsink. If are used the Q3-4 in packing TIPxxxx they can be placed straight above in PCB. If however they are used transistor in packing TO-3, then it will be supposed they are connected with short cables in the corresponding places on PCB.

R1-3-5-8-10 = 1Kohm
R2-7-11     = 100Kohm
R4-6        = 4.7Kohm
R9-12       = 100ohm
R13         = 47Kohm
R14-15      = 0.15ohm 5W
R16         = 1ohm 2W carbon 5%
R17         = 10ohm 1W carbon 5% 
C1          = 2.2uF 63V
C2          = 4.7uF 25V
C3-17       = 47uF 63V
C4-8-9      = 1nF 100V MKT
C5          = 47nF 100V MKT
C6          = 22pF ceramic
C7-11-12-13 = 100nF 100V MKT
C10         = 22pF ceramic 
TR1         = 10K Trimmer
D1-2        = IN4002
IC1         = LM391
Q1          = BD139
Q2          = BD140
Q3          = TIP2955
Q4          = TIP3055
L1          = See text

What's so special? Well, first of all - a very low harmonic distortion. Usually, manufacturers indicate the maximum power of its regular ingenious handicrafts with the harmonic content of 10%. At the same chip, CT at the maximum specified power is only 0,5%! Thus, it is the most honest of all mikruha I encountered.

In the chip implements two identical amplifier channels and features are given for the stereo mode of the amplifier. Circuit can also operate in mono - in bridge inclusion. In this case, the output power at CT = 0.5% of 120 watts. Other features remain virtually unchanged.

Skema rangakain amplifier 60W stereo LM4780

Skema rangakain amplifier 120W Bridged LM4780

LM4780 IC pin

Power amplifier is very important role, because the greater the power used amplifeir the better the sound can also be produced. by using the power amplifier that has a great power will strengthen the energy pounding bass tone or low tone, while the high tone or treble tone quality is maintained.

In skame series of images below presented the series of power amplifiers with 50 watts rms amplifier using NPN and PNP transistors 2n is 2n 7391 and 3055. if the scheme is not clearly visible Kilik so please double picture more clearly visible

Skema Rangkaian 50 Watt Rms Audio Power Amplifier

The amplifier is based on the commonly used class-AB complementary power amplifier with compound pair output transistors. The system uses a TL074 quad opamp to drive the output transistors. As can be seen from figure 1, A2 is used to set the voltage gain of the amplifier. Assuming the voltage gain of a common collector stage to be unity, the overall voltage gain of the amplifier is equal to (R4 / R3) + 1, i.e. the gain of a non-inverting OP-AMP (16 or 24dB, in this case). Since the output transistors are within the feedback loop of A2, A2 also acts to linearise the input characteristic of the complementary pair Q1/Q2 & Q3/Q4. This allows for greater mismatch between the NPN-PNP transistors.


The biasing to Q1 & Q3 is provided by R6, R7 & diodes D1 & D2. This arrangement biases the transistors just above cut-off and reduces crossover distortion. R6 must be adjusted to the highest value which eliminates crossover distortion. Ideally D1 & D2 should be mounted so they are in contact with the driver transistors - not the main heatsink.

To adjust R6 without an oscilloscope, start with R6 set to maximum, set the volume control R2 to get the minimum audible output with a suitable input source (such as a CD player which gives 0.65Vrms at line out), and listen for any "crackle" in the sound, especially that which seems to be riding on low frequency sounds. If a "crackle" is heard then reduce the value of R6 in very small steps, until the crackle (crossover distortion) becomes inaudible (it can't be eliminated, I feel).

As the output of opamp A2 is being pulled up by the biasing circuit, capacitor C5 must be connected between the output of A2 and ground to prevent the circuit from breaking into oscillations. The value of C5 is not critical, any value between 22nF to 100nF will do. The opamp A1 is a simple buffer which isolates the input circuit from the power stage. C1 & R1 are used to set the lower 3db frequency to around 15Hz, and to obtain an input impedance of about 100K. The upper 3db frequency is determined by R4 & C7, which in this case is approximately 30KHz. The schematic shows only one channel of the stereo amplifier. The amplifier can be used to drive speakers with impedance ranging from 3 Ohms to 8 Ohms, higher impedance speakers could be used but the power output will be substantially less.

The voltage gain of the amplifier can be increased by increasing R4 or decreasing R3, as long as the output swing is kept less than or equal to 3 Volts below the supply rails. This is due to the fact that the maximum output voltage of an opamp is always 2-3 Volts less than the supply rails, before it clips.

source sound.westhost.com

This amplifier does not claim to be "state of the art", and in fact the base design is now over 20 years old. It is a simple amp to build, uses commonly available parts and is stable and reliable. The design featured is a slight modification of an amp I originally designed many years ago, of which hundreds were built. Most were operated as small PA or instrument amps, but many also found their way into home hi-fi systems. The amp is capable of driving 4 Ohms, but it is starting to push the limits of the transistors, however, even when used at 4 Ohms, very few failures were encountered.

This amplifier circuit no output short circuit protection, so if speaker leads are shorted while the amp is working (with signal), there is a very real risk of the transistors being destroyed. Since this amp was built commercially, the savings were worth the risk - most of these amps were installed in the speaker box, so shorting was not likely (unless the loudspeaker voice coil shorted as happened a few times). Because of the cost of the devices used (minimal), it is a cheap amp to fix even if you do manage to blow it up.


If you do not have a dual output bench power supply - Before power is first applied, temporarily install 22 Ohm 5 W wirewound "safety" resistors in place of the fuses. Do not connect the load at this time! When power is applied, check that the DC voltage at the output is less than 1V, and measure each supply rail. They will be different, because of the zener diode feed resistance, but both should be no less than about 20V. If widely different from the above, check all transistors for heating - if any device is hot, turn off the power immediately, then correct the mistake.

Thanks to sound.westhost.com

Amplifier power is a circuit of electronics that is used to strengthen the power (or energy in general). In the field of audio, amplifier will amplify the sound signal (which has been expressed in the form of electric current) on the input it into electric current is stronger at the output. The amount of strengthening is often known by the term gain. Value of the gain is expressed as a function of frequency is called the transfer function.

So the gain is the result of the power output (Pout) and power at the input to its function in the form of frequency. The size of the gain, (G) is usually the Decibel (dB).

2N3055 Power Amplifier

Skema 2N3055 Power Amplifier . The optimal supply voltage is around 30V, but this amp work from 24 to 32V. The maximal input voltage is around 0.8 - 1V. As you can see, in this design the components have a big tolerance, so you can build it almost of the components, which you find at home. The and transistors can be any NPN type power transistor, but do not use Darlington types. The output power is around 150 Watt.

Skema Rangkaian 2N3055 Power Amplifier

capacitor C1 regulates the low frequencies (bass), as the capacitance grows, the low frequncies are getting louder.

capacitor C2 regulates the higher frequencies (treble), as the capacitance grows, the higher frequencies are getting quiter.

this is a class B amplifier, this means, that a current must flow through the end transistors, even if there is no signal on the input. This current can be regulated with the 500Ω trimmer resistor. As this current incrases, the sound of the amplifier gets better, but the end transistors are more heating. But if this current decrases, the transistors are not heating so much, but the sound gets worse.

Amplifier power is a circuit of electronics that is used to strengthen the power (or energy in general). In the field of audio, amplifier will amplify the sound signal (which has been expressed in the form of electric current) on the input it into electric current is stronger at the output. The amount of strengthening is often known by the term gain. Value of the gain is expressed as a function of frequency is called the transfer function.

So the gain is the result of the power output (Pout) and power at the input to its function in the form of frequency. The size of the gain, (G) is usually the Decibel (dB).

Skema Rangkaian Power Amplifier 200 watt

Equivalent Circuit of IC STK4050 II