Category: Electronics Projects

Electronic Thermometer Circuit

Engineeering Projects
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…

Read More

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

Engineeering Projects
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…

Read More

Door Ajar Alarm Circuit

Engineeering Projects
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…

Read More

Earth Quake Alarm Circuit

Engineeering Projects
design of earthquake sensor

Here is a simple project called earth quake alarm circuit. This circuit is divided into two sections. Geo mechanical detector (Earth quake sensor) Alarm circuit The earth quake alarm circuit is based on the principle that earth quake create slow and suddenly vibration. In order to detect this vibration geo mechanical detector is used. The construction of geo mechanical detector is shown in figure 2. Alarm Circuit | Earth Quake Alarm Circuit The alarm circuit is built around dual input, 4 NAND IC (CD4011) and a NPN transistor. Input of…

Read More

Tone Control for Guitar Amplifier Using 741

Engineeering Projects
circuit diagram of tone controller for guitar amplifier

Simple guitar amplifier circuit consist bass and treble circuit which is not appropriate. A sophisticated guitar amplifier must contain individual control for very string. Here is simple tone control circuit for guitar which has individual string control with bass and treble facility. The circuit of tone control for guitar amplifier is build around two most popular and low cost op-amplifier IC 741. This circuit is designed to control tone of 6-band of frequency 40Hz, 155 HZ, 625 Hz, 2.5 KHz and 10 KHz respectively. This frequency is control by variable…

Read More

Battery Voltage State Indicator using 741

Engineeering Projects
battery voltage state indicator circuit diagram

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…

Read More

Arduino Based Lie Detector

Engineeering Projects
light detector circuit using arduino

We have previously posted the the project lie detector, now here is is also a lie detector  using arduino.  Here is a simple tutorial to build a simple lie detector which will give visual indication  through LED arrangement whether the person speaks lie or truth.  The project uses a arduino duemilanove or uno. So the project is based on arduino. But our final circuit will be standalone circuit without attached arduino programmer. Circuit Description: Wiring diagram is very simple, we simply connected three LED to 3 different digital pins as…

Read More

8W + 8W Stereo Amplifier Circuit with Graphic Equalisers

Engineeering Projects
circuit diagram of 8W + 8W stereo amplifier

Various kinds of stereo amplifier are readily available in market. But if we ask for good quality stereo amplifier with graphic equaliser facility, it’s price become very high. The cheaper varieties are generally based on discrete transistors, and suffer from drawback such as uncontrolled hum, ineffective tone control, poor base response, thermal runway etc. the use of inter-stage transformers in such circuits reduces their versatility. Here you find the tutorial to build 8W + 8W Stereo Amplifier with Graphic Equalisers. Features | 8W + 8W Stereo Amplifier Circuit with Graphic Equalisers…

Read More

Automatic Voltage Stabilizer Circuit

Engineeering Projects
circuit diagram of automatic voltage stabilser

The project posted here is called an automatic voltage stabilizer circuit which solves almost all problems faced in the normally available stabilizer efficiently. With the help of the automatic voltage stabilizer circuit, we can keep the constant voltage at 230V when the voltage goes low as 170V and high as 250V automatically. The working strategy of the Automatic Voltage Stabilizer Circuit The working strategy of the circuit is very simple, this circuit energized one relay at a time from 170V AC upwards, and all relays and energized when 230V AC…

Read More

Overvoltage Protection Circuit

Engineeering Projects
circuit diagram of over-voltage protection circuit

Multiple appliances have been born to ease human efforts. And in the same run, numerous protective circuits are designed to ensure a long lifespan of those devices. We have seen those circuits claiming to protect appliances like refrigerators and air-conditioners from voltage fluctuations and brown-outs. An overvoltage protection circuit has been presented here serving multi-purpose security; under-voltage protection, switch-on delay, and regulation. Description of Overvoltage Protection Circuit Do not get worried with the overvoltage protection circuit diagram, though it looks complex, the circuit comprises building blocks we have been familiar…

Read More
  1. Pages:
  3. 1
  4. ...
  5. 28
  6. 29
  7. 30
  8. 31
  9. 32
  10. 33
  11. 34
  12. ...
  13. 47