45 watt Amplifier kelas B

45 Watt Class B amplifier Circuit of this very simple , straightforward but Rugged circuit, though intended for any high quality audio applications and, above all, to complete the series of articles recently started forming the Modular Preamplifier Control Center, is well suited Also to make a very Good Guitar or Bass amplifier

Skema rangkaian 45 watt amplifier kelas B

Note

• Power transistors Q8 and Q9 Can be Used satisfactorily: 2N3055/MJ2955, TIP3055/TIP2955, TIP35/TIP36, MJ802/MJ4502 amongst others.
• Power transistors Q8 and Q9 Should be mounted on a black, finned heatsinks as usual.

Technical data:

• Output power (1KHz sinewave): 45 Watt RMS into 8 Ohms - 69W RMS into 4 Ohms
• Sensitivity: 0.81V RMS input for 45W output
• Frequency response @ 1W RMS: 15Hz to 23KHz -0.2dB
• Total harmonic distortion @ 1KHz: 1W 0.008% 20W 0.008% 45W 0.016%
• Total harmonic distortion @10KHz: 1W 0.01% 20W 0.015% 45W 0.025%
• Unconditionally stable on capacitive loads

List Component

• R1: 18K
• R2: 3K9
• R3,R6: 1K
• R4: 2K2
• R5: 15K
• R7: 22K
• R8: 330R
• R9,R10: 10R
• R11,R12: 47R
• R13: 10R/1 Watt
• C1: 1µF/63V
• C2: 470pF/63V
• C3: 47µF/25V
• C4: 15pF/63V
• C6: 220nF/100V
• C6: 100nF/63V
• D1,D2,D3,D4: 1N4148
• Q1,Q2: BC560C
• Q3,Q4: BC556
• Q5: BC546
• Q6: BD139
• Q7: BD140
• Q8: 2N3055
• Q9: MJ2955

source

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Dynamic Microphone Preamplifier Dengan Gain Control

This is a 3 stage discrete Microphone amplifier circuit with gain control.The first stage built around Q1 operates in common base configuration. This is unusable in audio stages, but in this case, it allows Q1 to operate at low noise levels and improves overall signal to noise ratio. Q2 and Q3 form a direct coupled amplifier.

Skema rangkaian dynamic microphone preamplifier

As the signal from a dynamic microphone is low typically much less than 10mV, then there is little to be gained by setting the collector voltage voltage of Q1 to half the supply voltage. In power amplifiers, biasing to half the supply voltage allows for maximum voltage swing, and highest overload margin, but where input levels are low, any value in the linear part of the operating characteristics will suffice. Here Q1 operates with a collector voltage of 2.4V and a low collector current of around 200uA. This low collector current ensures low noise performance and also raises the input impedance of the stage to around 400 ohms. This is a good match for any dynamic microphone having an impedance's between 200 and 600 ohms.

Source

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150 Watt OCL Power Amplifier

This power amplifier OCL circuit deliver a blasting 150 watts to a 4 Ohm speaker jengkol use of transistors 2N3055 and MJ2955. The amplifier circuit is very CHEAPEST and Can be powered from 24 to 32 V/5A dual power supply. You must try this circuit. Its working great. Because Transisitor 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

Skema rangkaian 150 watt OCL power amplifier

Note:

• Use 24V/5A dual power supply.
• Connect a 50K POT in series with the input as volume control if you need.Not shown in circuit diagram

maximum rating Transistor 2N3055 NPN and MJ2955 PNP

• Collector-Base Voltage : 100 V
• Collector-Emitter Voltage: 70 V
• Collector-Emitter Voltage: 60 V
• VEBO Emitter-Base Voltage: 7 V
• IC Collector Current: 15 A
• IB Base Current: 7 A
• Total Dissipation: 115 W
• Storage Temperature: -65 to 200 oC
• Tj Max. Operating Junction Temperature 200 oC

Source: elektroarea.blogspot.com

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Op-Amp (LM741) Mic Preamplifier

Rangkaian op-Amp mic preamplifier

This Circuit of microphone preamplifier has a high quality and using a single power supply, suitable for dynamic or electret microphones. The op-amps Used Can be any low noise, high performance type, eg LM471, NE5534, TL071, OPA 371 etc.

Skema rangkaian op-Amp mic preamplifier

The design is a non-inverting amplifiers design, the input is applied to the non-inverting input of the op-amp pin 3 Which is in most cases. The input impedance is 23.5k, the overall voltage gain is determined by R2 and R1 and with the values of R2 and R1 on the circuit diagram the voltage gain (for mid band, 1KHz) is approximately 27.2dB.

Op-amp feature high gain bandwidth products, have a fast slewing rate and have extremely low noise. It is difficult to achieve the same performance using discrete components. Finally the overall signal to noise ratio has been calculated, the source was a 1k impedance microphone generating a 1mV pk-pk sine wave. An impressive result of 110dB S/n at 1KHz is achieved. In practice this figure will be lower and determined by the quality of the microphone used.

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Rangkaian 2 watt Amplifier BD139/140

This amplifier operates in Class AB mode with up to 2 watts of output power, the single 470R preset resistor controls the quiescent current PR1 flowing through the BD139/140 complimentary output transistors. Adjustment here, is a trade-off Between low distortion and low quiescent current. Typically, under quiescent conditions, current is about 15 mA, rising to 150 mA with a 50 mV input signal. The frequency response is shown below and is flat from 20Hz to 100kHz

Skema rangkaian 2 watt amplifier

PR1 470R controls the quiescent current flowing through the BD139/140 complimentary output transistors. Adjustment here, is a trade-off between low distortion and low quiescent current. Typically, under quiescent conditions, current is about 15 mA rising to 150 mA with a 50 mV input signal. The frequency response is shown below and is flat from 20Hz to 100kHz

This amplifier circuit is DC biased so that the emitters of the BD139 and BD140 are at approximately half supply voltage, to allow for a maximum output voltage swing. R9 and R10 provide a degree of temperature stabilization which works as follows. If the output transistors are warm, the emitter currents will increase. This causes a greater voltage drop across R9 and R10 reducing the available bias current. All four transistors are direct coupled which ensures:

• A good low frequency response
• Temperature and bias change stability.

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Rangkaian Microphone Pre-amplifier 2 Transistor

This microphone amplifier circuit is very simple, consisting of two levels. with wide dynamic regions, small noise, and can with a long cable about 50 meters. The battery supply is a good compromise: in this Manner The input circuit is free from mains low frequency hum pick-up and connection to The amplifier is more for simple, of due To The absence of mains cable and power supply. Using a stereo microphone the circuit must be doubled. In this case, two separate level controls are better than a dual-ganged stereo potentiometer. Low current drawing (about 2mA) ensures a long battery life.

Rangkaian Microphone Pre-amplifier

For better results use Enclosing the circuit in a metal case is highly recommended. output circuit of this microphone can directly connect to the Aux input of your amplifier through screened cable and suitable connectors.

List Component

P1: 2K2 Potentiometer
R1,R2,R3: 100K 1/4W Resistors
R4: 8K2 1/4W Resistor
R5: 68R 1/4W Resistor
R6: 6K8 1/4W Resistor
R7,R8: 1K 1/4W Resistors
R9: 150R 1/4W Resistor
C1: 1uF 63V Polyester Capacitor
C2,C3,C4: 100uF 25V Electrolytic Capacitors
C5: 22΅F 25V Electrolytic Capacitor
Q1: BC560C 45V 100mA PNP Transistor
Q2: BC550C 45V 100mA NPN Transistor

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Rangkaian Pengatur Volume Digital

Pengatur Volume Digital

Volume control is usually used Potensimeter. One drawback of the potentiometer is generated considerable noise, besides potentiometers also wear faster. To fix you can try using the following circuit. The circuit serves to replace your manual volume control in an amplifier. To adjust the volume size, you only need to press the Up or Down button. Following his schematics.

Rangkaian Pengatur Volume Digital

Note:

1. U1 you can get at Dallas Semiconductor.
2. S1 to raise the volume, S2 to lower the volume.
3. Input signal can not be less than -0.2 V.
   

This circuit can be used as a volume control, tone, contrast, brightness, and dimmer control. The circuit is extremely simple and compact requiring very Few external components with power supply Can Vary from 4.5V to 8V.

IC DS1669 Pinning

Pin Description IC DS1669

• RH - High Terminal of Potentiometer
• RW - Wiper Terminal of Potentiometer
• RL - Low Terminal of Potentiometer
• -V, +V - Voltage Inputs
• UC - Up Contact Input
• D - Digital Input
• DC - Down Contact Input

Standard resistance values IC DS1669

• DS1669-10 ~ 10 kΩ
• DS1669-50 ~ 50 kΩ
• DS1669-100 ~ 100 kΩ

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