Tag Archive: Audio

 Among the final amplifier we called. Regional Power Amp, will it work on several well-known as Class A, Class B, Class AB etc. Each class of the above, to honor the Class A was superior to the sound quality. best. However, class A power output to a low of 20 percent compared with a loss of power or the power consumption of about 5 times the power output. Therefore, the problem of heat Although it has not paid any audio. But anyway, despite the low-watt power, it also provides crystal clear sound quality than Class B and Class AB.

      Principles of integrated amplifier class A is IC1 – NE5532 to extend signal input through the C1 to increase 15-fold. The signal output from the pin 1, signal hemisphere positive through C2 to access Q1-BD139 and Q3-2N3055. is powered by Darling ton, amplifiers and signal the intensification of the negative side of C3 through the amplifier with the Q2-BD140 and Q4-MJ2955. This is the Darling ton, too.

Then the output signal from the positive side of the pin E of the Q3 and the negative side of the pin out of the E in Q4 through R10 and R11, to prevent short circuits and then output to the speakers. This will power up to 5 watts. The D1-D4 acts as a rectifier in the DC bias for Q1 and Q2. And VR1 is adjusted to a constant current bias is at work. The Q1-Q4 will be attached sheet cooled, Q3 and Q4, especially the thermal plate must be large. Because the circuit has high energy loss.


The TDA7377 amplifier is a class AB car radio amplifier able to work either in DUAL BRIDGE or QUAD SINGLE ENDED configuration.
With few external components TDA7377 can obtain high audio power performances .
The fault diagnostics makes it possible to detect mistakes during car radio set assembly and wiring in the car.
Main features of Tda7377 audio amplifier electronic project are : reversed battery protection ; short circuit protection ; very inductive loads ; diagnostic facility for clipping , out to gnd short ,out to Vs short
Tda7377 is available with 4 independent channels and can be used in applications with 4 or 2 speaker in single or bridge mode .
The stand-by function can be easily activated by means of a CMOS level applied to pin 7 through a RC filter and the device is turned off completely .
When the stand by functions is use some precautions have to be taken :
pin 7 cannot be directly driven by a voltage source whose current capability is higher than 5mA.

In practical cases a series resistance has always to be inserted, having it the double purpose of limiting the current at pin 7 and to smooth down the stand-by ON/OFF
In any case, a capacitor of at least 100nF from pin 7 to S-GND, with no resistance in between, is necessary to ensure correct turn-on.
The Vs range supported by this audio ic is 8 to 18 volts DC .
The power supply for this test circuit must be around 14.4 volts .
Maximum power ( 2×30 w) for this audio amplifier can be obtained in bridge mode for two channels at 4 ohms load impedance .


This siren circuit simulates police, fire or other emergency sirens that produce an up and down wail.

The heart of the circuit is the two transistor flasher with frequency modulation applied to the base of the first transistor. When the pushbutton is depressed, the frequency of oscillation climbs to a peak and when the button is released, the frequency descends due to the rising and falling voltage on the 22 uF capacitor. The rate of change is determined by the capacitor value and the 100k resistor from the pushbutton.  The oscillation eventually stops if the button is not depressed and the current consumption drops to a tiny level so no power switch is needed.

The 0.1 uF determines the pitch of the siren: A 0.047uF will give a higher pitch siren and a 0.001 uF will give an ultrasonic (at least for me, anyway) siren from 15 to 30 kHz which might have an interesting effect on the neighborhood dogs! The 33k resistor from the collector of the PNP to the base of the NPN widens the pulse to the speaker giving greater volume.

The flasher circuit drives a PNP transistor which powers the speaker. This transistor may be a small-signal transistor like the 2N4403 in most applications since it will not dissipate much power thanks to the rapid on-and-off switching. The 100 ohm and 100uF capacitor in series with the speaker limit the current to about 60 mA and they may be replaced with a short circuit for a louder siren as long as the transistor can take the increased current. The prototype drew about 120 mA when shorted which is fine for the 2N4403.

Transistor substitutions should be fine – try just about any small-signal transistors but avoid high frequency types so that you do not end up with unwanted RF oscillations.

This circuit simulates a chime similar to the sound many cars make when the keys are left in the ignition. The bottom two gates form a squarewave audio oscillator that drives the base of the 2N4401, turning it on and off at an audio rate. The top two gates produce a short low-going pulse about once per second that discharges the 10 uF capacitor through the diode. The voltage then jumps up and slowly decays through the 15 k collector resistor when the 2N4401 is conducting. The result is a squarewave on the collector of the 2N4401 that jumps up quickly then decays slowly. The darlington emitter-follower buffers the squarewave and drives a small speaker.  


The tone frequency is set by the 1000 pF capacitor and the cadence of the chime is set by the 0.1 uF capacitor. The 10 uF capacitor determines how quickly the chime dies out and the 3.3 k/3.3 uF soften the attack time of the leading edge of the chime. The volume is set by the 22 ohm resistor and 100 uF bypass capacitor. These values may be experimentally varied to produce the desired sound.

Typically audio amplifier stereo amplifier to a two amplifier. And if a mono amplifier is a single speaker. However this circuit command be present extended to the mono two loudspeaker.But not a equivalence or else serialization access.This makes it needless impedance of the speaker has altered.But will remain to utilize the spokeswoman as a replacement for of the resistance – Collection Peter (RC) of the transistor.The circuit can be alive prolonged to 2 loudspeaker itself. A1015

What time raising the power supply circuit and the audio to input. the audio sign coupling to through the C1 and R1 to increase with the Q1.Which Q1 serves like the Regional Pre amp amplifier to power up to a one point.already conveyance it to Q2.Which Q2 is connected to emitter follower circuit.be active as a driver amplifier intimate section from the pre amp section provides added power to drive the Q3 perform. and Q3 motivation provide while a Regional Power amp amplifier output to the spokeswoman.The opinion of the audio intimate through the VR1 and R2 to enter the pin B of Q2.To control the stability of working instead of well brought-up.This circuit is an output of 40 milliwatts watts of distortion of the gesture rate is by the side of 0.1 percent.And frequency response from 15 Hz – 200 kHz.

4 Channel Audio Mixer circuit



using TL084, 74HC4052, LM31B, 74HC000, 74HC73-2, LM6361N, 1N4148

TDA2822 is a monolithic integrated audio amplifier circuit that can be configured in stereo mode or bridge mode (BTL). The IC has low crossover distortion, low quiescent current and is available in 16 pin power DIP package. The TDA2822 can be operated from a supply voltage range of 3V to 15V. The main applications of TDA2822 are headphone amplifier, portable audio systems, mini radio, hearing aid, preamplifier etc. The IC can deliver an output power of 0.65W per channel into a 4 ohm loud speaker @ 6V supply voltage in the stereo mode and 1.35W into a 4 ohm loud speaker @ 6V supply voltage in the bridge mode.

TDA2822 IC configured in stereo mode is shown in fig1. The left channel input is applied to the non inverting input (pin1) of the first built in amplifier stage and the right channel input is applied to the non inverting input (pin 16) of the second built in amplifier. The inverting input of these built in amplifiers are connected to ground using separate 1000uF capacitors (C5 and C6). The amplified outputs (left and right) are available at pins 6 and 11 of the IC. The outputs are coupled to the corresponding speakers using capacitor C1 and C2 respectively. The resistor capacitor branch (0.1uF and 4.7 ohm) connected across speakers are meant for improving high frequency stability and preventing oscillations. C7 is the power supply filter capacitor.

The output power of TDA2822 amplifier can be increased by using it in mono mode using the bridge configuration and it is shown in Fig 2. The audio input is applied to the non inverting input of the first built in amplifier. The non inverting input of the second built in amplifier is grounded. The inverting input of these amplifiers are grounded using the C9, C11 capacitor branch. Branches R5, C8 and R6, C10 are meant for improving the high frequency stability and preventing oscillations. Capacitor C12 is used for filtering the power supply.


    The circuit can be assembled on a Vero board.
    The power supply can be anything between 3 to 15V DC.
    The power supply used for this circuit must be well regulated and free from any sort of noise.
    Optional 10K potentiometers can be added at the input lines for controlling the volume.
    It is better to mount the TDA2822 on an IC base.

 The LM386 is a versatile, small power amplifier designed for use in low voltage consumer applications. The gain is internally set to 20 to keep external part count low, but with the addition of an external resistor and capacitor between pins 1-8 the gain can be set to any value from 20 to 200.
The inputs are ground referenced and the output automatically biases to one-half the supply voltage. The quiescent power drain is only 24 milliwatts when operating from a 6 Volt supply, making the LM386 ideal for battery operation.

To make the LM 386 a more versatile amplifier, 2 pins (pin 1 and 8) are provided for gain control. With pins 1 and 8 open the internal 1.35k resistor sets the gain at 20 (26 dB). If a capacitor is placed between pin 1-8, bypassing the built-in 1.35k resistor, the gain will go up to 200.

If a resistor is placed in series with the capacitor, the gain can be set to any value from 20 to 200. Gain control can also be done by capacitively coupling a resistor or FET transistor from pin 1 to the ground.


  Operating Supply Voltage (VS) = 4v – 12v

  The output power (POUT)
       for LM386N-1, LM386M-1 at VS = 6V, RL = 8ohms, THD = 10% is 250-325 mW
       for LM386N-3           at VS = 9V, RL = 8ohms, THD = 10% is 500-700 mW
       for LM386N-4           at VS = 16V, RL = 32ohms, THD = 10% is 700-1000 mW.