Voice Recording and Play Back Circuit using APR9600

Circuit diagram of Recording and playback with auto rewind option

There are various types of voice processing chip (IC) with various features for speech compression and processing is readily available. Here is projects called Voice recording and play back using chip (APR9600). An APR9600 is a single chip voice recorder and playback device from Aplus integrated circuits. This chip used flash non volatile memory to store up to 256 voltage levels. i.e. for 32 to 60 seconds. This chip have many features like, one can select sample rates with consequent quality and recording times. Microphone amplifier, automatic gain control (AGC)…

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Mosquito Repeller Circuit

circuit diagram of mosquito repeller

Here is a simple circuit called mosquito repeller in the series of easy electronic project. The circuit of mosquito repeller uses few passive components. Circuit Description and Working Principle of Mosquito Repeller Circuit: The circuit of mosquito repeller is so simple that any-one can understand. The input of 220 volt AC from mains is directly given to the circuit; two resistors are connected in parallel as current divider circuit. Neon lamp is used as indicator to check whether the circuit works properly or not. An aluminum plate is connected to…

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Disco Light Circuit

circuit diagram of disco light

Blinking and shimmering of lights in disco keep everyone amazed, the entire design cost of which might seem high. A circuit is presented hereby is of disco light making use of low-cost CMOS chip CD4011B, which is a two-input quad NAND gate. Along with two particular gates; G1 and G2 as shown in the figure below, it works as an RC oscillator forming clock oscillator gates. Circuit Description of Disco Light Circuit Here the two input terminals of the CMOS chip are coupled together to form an inverter. And, again…

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Touch Switch-Cum-Heat Operated Switch

circuit diagram of touch switch cum heat operated switch

We are updating day by day with different projects. Now, here we are going to post a very simple project using a few active as well as passive components called dual switches. As its name, it can be used as a touch switch as well as heat operated switch. Thus, we are calling it Touch Switch Cum Heat Operated Switch Circuit Description Touch Switch Cum Heat Operated Switch The circuit of the touch switch cum heat operated switch is very simple and easily understandable. It comprises three general-purpose transistors. The…

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Clap Switch Cum Touch Switch

circuit diagram of clap switch cum touch operated switch

Various Switching circuits including clap switch, touch witch heat switch is already posted. Now, here is two in one switching circuit i.e. clap switch cum touch switch with a facility of timer. Circuit Description Clap Switch Cum Touch Switch This circuit uses a timer IC NE555 (IC2) and audio amplifier IC TBA810 (IC1). TBA810 is a 7-watt audio amplifier IC which is used to amplify the audio signal coupled from audio transformer X1. Here we used a loudspeaker as a sound sensor. The audio transformer of 3 volts is connected…

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Bass Booster Circuit using Op-Amp 741 IC

bass booster circuit design

Here is one another basic project call bass booster using op-amp 741 IC. The circuit bass booster increases beat frequency without affecting high frequency. Description of Bass Booster Circuit using Op-Amp 741 IC The circuit of bass booster shown in figure 1 is divided into two main section i.e. bypass high frequency and boost section. The input of this circuit is connected to the output of pre-amplifier circuit and it’s output to input of power amplifier circuit. When audio signal is given to the input, high frequency is passed through…

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DIY Headphone Amplifier using 741 IC

circuit diagram of DIY headphone amplifier

Various type of amplifier and pre-amplifier circuit has appeared in this website in amplifier and pre-amplifier section. The circuit posted here is of DIY headphone amplifier which is suitable for headphone or 8-ohm speaker or more impedance. The circuit is so designed that it has no risk of overloading or distortion of either the circuit or headphone. Circuit Description DIY Headphone Amplifier using 741 IC The heart of the circuit headphone amplifier is op-amp 741 which provide suitable gain where the transistor T1 and T2 are used to drive low…

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Electronic Thermometer Circuit

electronic thermometer using 741 IC circuit

A number of measurement circuits have appeared on this website. The project posted here is of Electronic Thermometer Circuit using op-amp 741. This circuit is suitable to measure temperature from 00C to 500C using a linear scale am-meter. The range can be extended up to 1000C using 100 microamperes. Circuit Description of Electronic Thermometer Circuit using 741 IC The circuit is self-explanatory for the experienced hobbyist and performs its task with a minimum number of components. The operational amplifier is used in compactor mode. The diodes D1 and D2 are used…

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High/Low Voltage Cut-out Using Op-Amp 741

high low voltage cutout circuit diagram

Various type of high low circuit can be designed using different type of IC. Here the circuit shown of high/low voltage cutout using two op-amp IC 741, with hold on facility. PARTS LIST OF HIGH/LOW VOLTAGE CUT-OUT USING OP-AMP 741 Resistor (all ¼-watt, ± 5% Carbon) R1, R7 = 10 KΩ R2 = 1 KΩ R3 – R6 = 100 KΩ R8 = 100 Ω VR1 = 10 KΩ Semiconductors IC1, IC2 = 741 ZD1 = 9.1V D1, D2, D3 = 1N4001 T1 = SL100 Miscellaneous SW1 = ON/OFF Switch…

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Door Ajar Alarm Circuit

circuit diagram of door ajar alarm circuit

Here is an another alarm circuit in the section of sound generator, the project posted here is of door ajar alarm circuit which alerts in every ten seconds that your door is open. Circuit Description of Door Ajar Alarm Circuit The heart of the circuit is 14-stage ripple carry binary counter IC CD4060. The working principle of the circuit is very simple, when high input at reset pin (pin 12) is given all the output becomes low and vice-versa.  Switch SW1 is used as door open/close sensor, when the door…

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