Sensor Circuits

The LM35 temperature sensor provides an output of 10 mV/C for every degree Celsius over 0C. At 20C the output voltage is 20 10 = 200 mV. The circuit consumes 00...

Views: 47 | Votes: 106 | Comments: 0 | Rating: 9 | Rank: 5 | Added: Apr 1, 2013 |

In this circuit, audio fed to the control channel is amplified and rectified by Dl and D2. This dc level activates LED D3 via Q2. The light from D3 causes R9, a light-dependent resistor to decrease resistance. As Rll (audio gain) is set higher, more audio is present at the output of Ql. Audio fed into J2 is shunted to ground via R9 and less of this audio appears at J3...

Views: 10 | Votes: 84 | Comments: 0 | Rating: 1 | Rank: 5 | Added: Mar 30, 2013 |

Assume the correct phase sequence to be VA-VB-VC. The circuit terminals are connected such that Tl gets connected to phase A and T2 to phase B. The capacitor advances the voltage developed across R2 due to phase "B" by — 60°, while the voltages developed across it by phase "A" is in phase with VA as shown in Fig. 69-1. The net voltage developed across R2 ~ zero, the neon lamp is not energized, thereby signaling correct phase sequence. If terminal T2 gets.....

Views: 5397 | Votes: 90 | Comments: 0 | Rating: 9 | Rank: 6 | Added: Mar 29, 2013 |

A positive going input charges C through the IN4148 and R. The diode keeps the scs off. ..

Views: 941 | Votes: 103 | Comments: 0 | Rating: 2 | Rank: 4 | Added: Mar 28, 2013 |

The main objective of this project is to detect rising water level in a river at a reasonable distance from the rail track/ roadways and intimate that to the respective authorities through SMS, to take appropriate action. For example, railways face major challenges in prior detection of possible flash flood along the track, which might cause accidents. In this proposed system, water level rise is sensed at a considerable distance from the tracks and necessary action.....

Views: 17 | Votes: 44 | Comments: 0 | Rating: 9 | Rank: 10 | Added: Mar 23, 2013 |

The timing cycle is continuously reset by the input pulse train. A change in frequency, or a missing pulse, allows completion of the timing cycle which causes a change in the output level. For this application, the time delay should be set to be slightly longer than the normal time between pulses..

Views: 3163 | Votes: 30 | Comments: 0 | Rating: 2 | Rank: 5 | Added: Mar 17, 2013 |

This circuit can detect the positive peaks for signal frequencies higher than 5 MHz. It yields ±1% accuracy for 400 mV to 4 V pk-pk signal amplitudes on sine, square, and triangular waveforms. The Am685 comparator output increases whenever VrN is a greater negative voltage than Vour; the high comparator output, in turn, charges C1 in a positive direction. The CA3140 op amp amplifies the C1 voltage with respect to the ECL-switching-threshold voltage ( -1.3 V).....

Views: 6 | Votes: 66 | Comments: 0 | Rating: 3 | Rank: 5 | Added: Mar 14, 2013 |

The project is designed to actuate a load when IR rays are interrupted by any object. his is helpful in industries for sensing movement of material in a conveyor belt for any action to be taken. The project uses 38 KHz IR signal generated feeding an IR diode which is received by tuned IR receiver. These IR sensors are interfaced to a microcontroller of 8051. The IR transmitter continuously transmits rays over the receiver and when these rays are blocked by any object.....

Views: 15 | Votes: 59 | Comments: 0 | Rating: 6 | Rank: 10 | Added: Mar 8, 2013 |

ICla and IClb are wired as a slow astable multivibrator and IClc-ICld are wired as a fast astable. The output of the slow astable modulates the frequency of the fast astable, and the output of the fast astable is fed to the external speaker via the Ql VMOS power FET amplifier stage. ..

Views: 191 | Votes: 17 | Comments: 0 | Rating: 6 | Rank: 6 | Added: Feb 22, 2013 |

This circuit is useful for signal-processing sonar data recorded on an instrumentation-quality analog tape recorder. The envelope detector utilizes ready available parts, and furnishes accuracy beyond 100 kHz. Two LM301 op amps connected as precision absolute-value circuits use 2-pole frequency compensation for increased slew rate. ..

Views: 10 | Votes: 35 | Comments: 0 | Rating: 0 | Rank: 5 | Added: Feb 18, 2013 |

The MC1596/MC1496 makes an excellent SSB product detector. This product detector has a sensitivity of 3 microvolts and a dynamic range of 90 dB when operating at an intermediate frequency of S MHz. The detector is broadband for the entire high frequency range. For operation at very low intermediate frequencies down to 50 kHz the 0 /aF capacitors on pins 7 and 8 should be increased to 1 /aF. Also, the output filter at pin 9 can be tailored to a specific intermediate.....

Views: 4330 | Votes: 12 | Comments: 0 | Rating: 4 | Rank: 5 | Added: Feb 15, 2013 |

The project is designed to build an obstacle avoidance robotic vehicle using ultrasonic sensors for its movement. A microcontroller of 8051 family is used to achieve the desired operation. A robot is a machine that can perform task automatically or with guidance. Robotics is generally a combination of computational intelligence and physical machines (motors). Computational intelligence involves the programmed instructions. The project proposes robotic vehicle that has.....

Views: 24 | Votes: 69 | Comments: 0 | Rating: 9 | Rank: 10 | Added: Feb 9, 2013 |

The output of the detector contains a term related to the cosine of the phase angle. Two signals of equal frequency are applied to the inputs. The frequencies are multiplied together, producing the sum and difference frequencies. Equal frequencies cause the difference component to become de, while the undesired sum component is filtered out. The de component is related to the phase angle by the graph of Fig. 70-2B. At 90°, the cosine becomes zero, while being at.....

Views: 14 | Votes: 55 | Comments: 0 | Rating: 1 | Rank: 5 | Added: Feb 8, 2013 |

The output goes high when the supply falls below a value determined by zener diode Dl. If Dl is a 5.6-V zener, the op..

Views: 4 | Votes: 85 | Comments: 0 | Rating: 5 | Rank: 5 | Added: Feb 7, 2013 |

Many applications require analog signals to be sensed and digital signals to be controlled. A way to detect these p..

Views: 6 | Votes: 71 | Comments: 0 | Rating: 5 | Rank: 5 | Added: Feb 5, 2013 |

The circuit uses a 741 op amp operating as an inverting amplifier to amplify the voltage produced by an 8-ohm speaker used to detect any sounds. The feedback resistor R3, a 1-megohm potentiometer used to vary the gain of the amplifier determines the sensitivity of the circuit. When Si is closed in the (SET)-position and a sound is applied to the speaker, SCR1 is turned on...

Views: 884 | Votes: 100 | Comments: 0 | Rating: 8 | Rank: 7 | Added: Feb 4, 2013 |

At the heart of this simple circuit is the well-known type KTY10 temperature sensor from Siemens. This silicon sensor is essentially a temperature-dependent resistor that is connected as one arm in a bridge circuit here. Preset PI functions to balance the bridge at 0C. At that temperature, moving coil meter Ml should not deflect, i.e., the needle is in the center position. Temperature variations cause the bridge to be unbalanced, and hencc produce a proportional.....

Views: 7 | Votes: 80 | Comments: 0 | Rating: 8 | Rank: 5 | Added: Feb 4, 2013 |

The 555 is a monostable that wants a negativegoing trigger. If the pulse you"re feeding it with is positive-going, you can run it through an inverter made up of either an inverting gate or, if you"re tight on space, a single transistor. Both ways are shown. The circuits shown in Fig. 25-9b are edge detectors as well, and are usually referred to as half monostables, since they can"t be used in every application. ..

Views: 1 | Votes: 103 | Comments: 0 | Rating: 8 | Rank: 5 | Added: Feb 3, 2013 |

Useful for checking TV remote controls, IR-based alarm systems, and IR sources, this circuit causes LED1 to turn on for two sec..

Views: 7 | Votes: 93 | Comments: 0 | Rating: 4 | Rank: 5 | Added: Jan 7, 2013 |

These circuits are used for product detection of single-sidebound (SSB) and CW signals. BFO injection is typically..

Views: 10 | Votes: 83 | Comments: 0 | Rating: 4 | Rank: 5 | Added: Jan 5, 2013 |