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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Thermal Touch Switch using op-amp 741
Various types of switch circuits like a light operated switch, sound operated switch, etc is already posted on www.bestengineeringprojects.com. Now here is a thermal touch switch that automatic on and off due to the increase and decrease of pre-defined temperature. This type of circuit is useful to operate fans, cooler, etc. Circuit description of thermal touch switch using operational amplifier 741 The circuit comprises an operational amplifier IC (IC1), silicon diode (D1 and D2), and a few passive components to complete the circuit. Diode D1 is used here as a…
Read MoreVoltage into Frequency Converter Circuit using 741 IC
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…
Read MoreWind Sound Generator Using IC 741
Various sound generator projects is already posted in bestengineeringprojects.com in alarm and sound generator section. Now here is one another sound generator circuit using most popular and versatile operational amplifier IC 741. The circuit posted here is of wind sound generator using IC 741 produces wind sound. Circuit Description of Wind Sound Generator Using IC 741 The circuit of wind sound generator comprise operational amplifier 741, two NPN transistors (BC148) and some passive components (resistors and capacitors). Transistors T1 and T2 generate wind sound. A jumper is connected to emitter…
Read MoreDC Volt Polarity Indicator Using IC 741
Now, here is another basic electronic project using the most versatile operational amplifier IC 741 “DC Volt Polarity Indicator”. Using the project DC volt polarity indicator one can know the positive and negative polarity of DC volt. This project is very useful for electronics hobbyists to check either battery polarity or polarity at the output of the DC source. The circuit present here is so simple that even electronics beginners can understand how the circuit works. Circuit Description of DC Volt Indicator Using IC 741 The heart of the circuit…
Read MoreMulti Tone Generator Circuit
Here one another sound generator project is added is section of alarm and sound generator projects. We have tested and posted dozens of sound or tone generator projects. Now, here is multi-tone generator circuit which produces eight different types of tones. The tones produced by the circuit multi tone generator are of Bell, Ambulance Siren, Whistle, Machine gun Sound, Jingle, Police siren, Birds and Dual sound. Circuit Description of Multi Tone Generator Circuit The heart of the circuit multi tone generator is UM5561 IC (IC1) and the entire circuit is…
Read MoreOperational Amplifier 741 Tester
The op-amp IC 741 is a DC-coupled, high gain differential amplifier with external negative feedback. IC 741 is characterized by the almost infinite open-loop gain (100,000), almost infinite input impedance (2MΩ), and almost zero output impedance (75Ω).  IC 741 is the most popular, cheap, and easy-to-use op-amp. Various type of circuit is designed using Op-amp 741 out of which some are voltage follower, current to voltage converter and vice versa, summing amplifier, etc. Various type of circuit based on op-amp 741 is already posted in bestengineeringprojects.com on the op-amp section.…
Read MoreFlasher Circuit
Replacement of burnt LML vespa flasher costs around $ 2.5. The flasher can be replaced with the help of the circuit sows here. It costs around $1.2. Circuit Description of LML Vespa Flasher The circuit of LML vespa flasher consists of a multivibrator built around transistors T1 and T2. The time period of the pulse can be varied by changing the values of R1, R2, C1 and C2. The values shows in the circuit are chosen to match the flasher with the flashers available in the market. Gates of TRIAC…
Read MoreMains Supply Interruption Indicator Circuit
The Mains Supply interruption indicator circuit can be used in applications where it is necessary to know whether the mains supply has been continuous or not. The circuit mains supply interruption indicator will be useful for monitoring mains supplies to recording equipment, especially in the recording of computer software tapes, where the slightest interruption in the mains supply will cause an error in the data being recorded. It can also be used with digital clocks working on mains. An interruption in the mains supply will cause an LED to flash…
Read MoreVariable Switching Power Supply
Various type of power supply circuit from basic regulated power supply to advanced digital control power supply unit is already posted on bestengineeringprojects.com. Now here one more power supply circuit is posted and can be used to provide up to 300mA and voltage between 6V to 13V. Circuit Description of Variable Switching Power Supply The input AC is stepped down using a step-down transformer T1 to 18V AC which is further rectified by a bridge rectifier. The rectified output is filtered by 1000 capacitor C1. The Zener diode ZD1 is…
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