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Electronic circuit applications
Published in Joe Cieszynski, David Fox, Electronics for Service Engineers, 2012
The phasor diagram enables the phase of the resultant voltage Vs to be shown and reveals that a phase shift of 60° has occurred. Since the phase shift oscillator has three RC networks the result is a phase shift total of 180°. The signal fed back is now in the same phase as the input so positive feedback has been achieved and oscillation will occur. The frequency of operation is determined by the time constant produced by the values of R and C. Different values of R and C give different time constants and therefore different frequencies of oscillation. The role of the transistor is important since it must provide enough gain to maintain oscillation. Experimentation shows that a minimum gain of 29 is needed. The frequency of operation can be determined using the following formula: f=12π√6RC
The Feedback Control Loop
Published in Norman A. Anderson, Instrumentation for Process Measurement and Control, 2017
Figure 7-9 shows a free-running oscillator in which the required energy is introduced through feedback. This circuit is called a phase shift oscillator. It consists of a transistor amplifier and a feedback path comprised of three resistance-capacitance combinations. This circuit is important because it is a simple illustration of the manner in which an ordinary amplifier can be made to oscillate simply by use of feedback.
Radiation study of TFET and JLFET-based devices and circuits: a comprehensive review on the device structure and sensitivity
Published in Radiation Effects and Defects in Solids, 2023
Since the radiation-induced oxide trapped charges are lesser in Silicon Carbide (SiC) devices than in Silicon MOSFETs, they are used in power electronics to sustain a high radiation environment and thus making SiC MOSFET radiation resilient (25–29). Akturk et al. studied that SiC power MOSFET remains operational even after exposing it to radiation of more than 100 K rad (30). The effect of radiation on the 4H-SiC CMOS trans-impedance amplifier reveals that the device shows robust performance in a harsh environment (31). Under radiation, n-channel Transparent Gate Recessed Channel (TGRC) MOSFET shows more sensitivity than conventional MOSFET (32). Downscaling makes MOSFETs more prone to SEE, for continuing the trend of scaling many new materials and new devices are developed (33,34). Combined effects of TID and SEE on vertical double-diffused MOSFET observed under the exposure of gamma radiation show more damage to the device as larger Interface Trap Charges (ITC) are generated (35,36). Radiation effect on MOSFET-based RC phase shift oscillator shows that gamma radiation exposure affects the frequency of oscillation (37).