6W amplifier using TA7222AP

Description. Here is the circuit diagram of a 6W amplifier using the TA7222AP from Toshiba.TA7222AP is an excellent integrated audio amplifier which can deliver 5.8W to a 4 Ohms load at 12V supply voltage. The IC has very good features like, muting function, low distortion, high ripple rejection, short circuit protection, thermal shut down etc. This amplifier can be operated from 8 to 12V and this makes it ideal for car radio applications. Circuit diagram. Notes. The circuit can be assembled on a Vero board. Use 12V DC for powering the circuit. The IC must be heatsinked. Speaker can be…

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Ding-Dong sound generator

Description. This is the circuit diagram of a ding dong sound generator based on two NE555 timer ICs.The circuit is designed to toggle between two adjustable frequencies to produce the ding dong sound. The first NE555 (IC1) is wires as an astable multivibrator operating at 1Hz. The frequency of the second NE555 (IC2) is modulated by the output from the first IC. This is attained by connecting the output of first IC to the control pin (pin5) of the second IC. The tone of the sound depends on the frequency of the second IC and the changeover time depends on…

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Stereo balance indicator

Description. This is one of the simplest stereo balance indicator circuit that you can have. The circuit will give a visual indication (using two LEDs) proportional to the difference in balance between the left and right channels of a stereo system. The circuit is based on a uA741 opamp IC. The IC compares the signals from the two channels and when both signals are in balance, the output of the IC will be steady and the LEDs will glow in same brightness. Unbalance in sound causes the two LEDs to vary in brightness proportionally. Circuit diagram. Notes. The circuit can…

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Dynamic microphone amplifier using transistors

Description. Here is the circuit diagram of a simple dynamic microphone amplifier using two transistors. The amplification factor of this circuit is around 150 and can handle signals from 50Hz to 100Khz.These features make it ideal for audio applications. The audio signal from the microphone is coupled to the base of Q1 via the capacitor C1 and resistor R3. Q1 works as a preamplifier here. The preamplified signal will be coupled to the base of Q2 for further amplification. Resistor network comprising of R4, R5 and R6 provides the necessary negative feedback. Final output signal will be available at the…

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40W audio amplifier

Description. This is a very excellent 40W power amplifier design using TDA2030 IC and two transistors. The circuit employs only few components and does not require a dual power supply. The input signal is coupled to the non inverting input of TDA2030 through the DC decoupling capacitor C5. The TDA 2030 performs the major part of voltage amplification. As the IC performs amplification, the power supply current to the IC varies according to the input signal. The variations in the positive supply pin are coupled to the base of Q1 and variations in the negative supply pin are coupled to…

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Preamplifier for dynamic microphones.

Description. Here is a low noise preamplifier design for dynamic microphones. The circuit is based on the uA739 IC from Fairchild Semiconductors. uA739 is a dual audio operational amplifier with high gain and excellent stability. Out of the two opamps available in the IC, only one is used here. The audio signals from the microphone are coupled to the non inverting input of IC1 through the capacitor C1 and resistor R1. C1 performs input DC decoupling. The R1, C2 network bypasses the unwanted high frequency signals from the microphone. A fraction of the output is fed back to the inverting…

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FET based audio preamplifier.

Description. This is the circuit of a based audio preamplifier which has very low noise. One FET and one BJT are used in this circuit. The audio signal to be amplified is coupled to the base of FET Q1 using capacitor C1 and resistor R3.Base of transistor Q2 is coupled to the drain terminal of FET Q1. Transistor Q2 provides additional current gain. The final signal will be available at the collector of Q2.Capacitor C3 provides necessary negative feedback, which improves stability. Capacitor C2 is an output DC decoupling capacitor. Since an FET is used in the input stage this…

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Jet engine sound generator

Description. This jet engine sound generator circuit is based on the sound generator IC HT2844P from Holtek Semiconductors. This particular IC can make four sounds namely low speed sound of jet engine, high speed sound of jet engine, missile sound and machine gun sound. Each of these sounds can be activated by connecting the pins 12, 13, 14and 15 to ground by using the respective push button switches. Resistor R3 can be used for manually increasing or decreasing the speed.LED D1 gives a visible indication of the sound. Circuit diagram. Notes. The circuit can be powered from a 3V battery….

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250mW audio amplifier

Description. Here is a very simple three transistor audio amplifier circuit that can deliver 250mW to a 8Ohm speaker. Complementary transistors BC337 and BC227 (Q3 and Q2) are used as the output pair. Transistor Q1 (BC 547) acts as the preamplifier.POT R5 can be used as a volume control. Capacitor C1 decouples the DC from the audio source. Resistor R2 ensures better stability for the amplifier.This amplifier is very suitable for application in small radio sets and as a preamplifier in high power audio amplifiers. Circuit diagram. Notes. The circuit can be powered from 9V DC. Assemble the circuit on…

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10W amplifier using TDA2003.

Description. Here is the circuit diagram of a 10W audio amplifier using the popular TDA2003 IC from SGS Thomson. The IC can easily deliver 10W to a 4 Ohms load at 18V DC supply voltage. The IC can be also operated from 12V and that makes it applicable in car audio systems. The useful features of TDA2003 includes short circuit protection between all pins, thermal overload protection, low harmonic distortion, low cross over distortion etc. The circuit given here is designed as per the datasheet from the manufacturer and found to be working fine. Capacitor C7 performs the job of…

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