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Operational Amplifiers
Published in Michael Olorunfunmi Kolawole, Electronics, 2020
Multivibrator is nothing but a two-stage amplifier, operating in two modes. The modes are called states of the multivibrator. Basically, the output of the first stage is fed to the input of the second stage while the output of the second stage is fed back to the input of the first stage. These input signals drive the active device of one stage to saturation while the other is cut off. The new set of signals, generating exactly opposite effects, follows. As a result, the cutoff stage now saturates while the saturated stage becomes cutoff. Primarily, there are three types of multivibrator circuits, namely (a) bistable multivibrator, which we have just discussed, (b) astable multivibrator, and (c) monostable multivibrator. The astable and monostable types have been discussed in Chapter 2.
Electronic Circuits
Published in Dale R. Patrick, Stephen W. Fardo, Electricity and Electronics Fundamentals, 2020
Dale R. Patrick, Stephen W. Fardo
A monostable multivibrator has one stable state of operation. It is often called a one-shot multivibrator. One trigger pulse causes the oscillator to change its operational state. After a short period of time, however, the oscillator returns to its original starting state. The RC time constant of this circuit determines the time period of the state change. A monostable multivibrator always returns to its original state. No operational change occurs until a trigger pulse is applied. A monostable multivibrator is considered to be a triggered oscillator.
Digital Timing and Signals
Published in Dale Patrick, Stephen Fardo, Vigyan ‘Vigs’ Chandra, Electronic Digital System Fundamentals, 2020
Dale Patrick, Stephen Fardo, Vigyan ‘Vigs’ Chandra
Discrete bipolar transistors can be connected to form a clock or a time-base generator. Transistors Q1 and Q2 of Figure 7-2 are connected in an astable multivibrator circuit configuration. An astable multivibrator is basically a wave-form generator that is self-starting and operates continuously for long periods of time. The shape of the waveform and its frequency are primarily determined by an RC network applied to each transistor.
Fabrication of a WO3 Conductometric Activated Thin Film Sensor for Resistance-to-frequency Conversion Based Sensing Application
Published in IETE Journal of Research, 2022
Bikram Biswas, Anup Dey, Subhashis Roy, Subir Kumar Sarkar
Figure 4 shows the experimental set up for the ethanol vapor sensor. The sensor chamber is made of glass (length 30 cm and diameter 4 cm). The sensor is inserted into the chamber (by contact connection). The temperature controller (TC) is used to attain the operating temperature of the sensor. Resistive heating coil (≈ 8 cm of the constant heating zone, with temperature accuracy ±10C) is used internally in temperature controller for heating purpose. The gas flow and mixing ratio are precisely monitored and controlled with the help of mass flow controller (MFC). The homogeneous mixture carrying the desired percentage of the target vapor is fed into the chamber with a flexible PVC pipe. During testing, the gas pressure on the sensor is maintained at 1 atm. An automated data acquisition system is used to measure the change in resistance under various operating temperatures and vapor concentrations. The sensor is connected to a signal conditioning circuit which is a 555 timer based astable multivibrator. The output of the bread board circuit is measured by an oscilloscope.