Category: IC 741 Based Projects

Here is a simple circuit using op-amp 741 called “Battery voltage state indicator using 741” used to indicate whether the battery is charged or not. The circuit shows three states of battery voltage i.e. charged, discharged, and normal using three different color LEDs (LED1, LED2, and LED3). you may also like other battery state indicator circuit Battery level state indicator (Designed using general-purpose NPN transistor 2N2222, indicate two states of battery i.e. undercharged and overcharged). 10 Level battery Charge Indicator Circuit (Designed using comparator IC LM3914, used to indicate the…

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For laboratory work, an accurate temperature deviation indicator is more effective than a sophisticated thermometer. The electronic device temperature deviation indicator using 741 can register a difference of 0.20C between the thermal sources and display it with the appropriate direction of variation. It can be used as a heater coil controller to maintain the equilibrium level. Circuit Description of Temperature Deviation Indicator using op-amp 741 The circuit of temperature deviation indicator using op-amp 741 is simple and self-explanatory. Two silicon diodes (D3 and D4) complete a bridge network and act…

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Here is a simple project called listening bug circuit using 741 using the most popular op-amp IC 741. This circuit can be used for spying because by using this circuit we can hear any conversation held in any other room or we can say using this circuit one can hear the conversation held in another room. This circuit can also be used for baby monitoring. Also, check our Listening Bug Circuit using op-amp LM386. Description of Listening Bug Circuit Using 741 The circuit of the listening bug shown in figure…

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The frequency of the AF oscillator can be varied over a wide range. It can therefore be used for AF amplifier testing and also as a code practice oscillator. Circuit Description of A Variable Audio Frequency Oscillator Using Op-amp 741 The circuit of variable audio frequency oscillator using op-amp 741 is mainly a Wein Bridge oscillator whose frequency is varied using the gang condenser. While using the IC1 741 (operational amplifier), the use of a split power supply has been avoided by using capacitors C1 and C2, for R4*, a 150-Ω…

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Various types of basic electronic projects using operational amplifier-based projects are already posted on bestengineeringprojects.com. Now, here is another basic project using an operational amplifier called a microphone amplifier using 741. The circuit microphone amplifier amplifies weak electric signals converted by the microphone to the necessary level. More other circuits using microphones are posted on bestengineeringprojects.com Dynamic Microphone Preamplifier Circuit Listening Bug Circuit using op-amp LM386 DIY Hearing Aid Circuit using 555 Sound Activated 0-30 Minutes Timer Circuit Arduino-Based Automatic Call Answering Machine Sound detector circuit using op-amp 741 Circuit…

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IC 741 is the most used and popular operational amplifier IC, because of its unique feature and low price. Various op-amp 741-based projects are already posted in the operational amplifier-based projects section. Now, here is a simple project using a couple of op-amps 741 IC called voltage into frequency converter. Description of voltage into frequency converter Circuit using 741 IC The circuit of voltage into frequency converter consists of a couple of op-amp 741, a couple of transistors, and a few passive components (resistors). The voltage of 0.5V to 15V…

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