China
Africa
Explore chapters and articles related to this topic
Oscilloscope Voltage Measurement
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
The world of oscilloscopes is divided into two general categories: analog and digital. The first oscilloscopes were analog. These products are based on the direct-view vector cathode-ray tube (DVVCRT or CRT for short). The analog oscilloscope applies the input signal to the vertical deflection plates of the CRT where it causes the deflection of a beam of high-energy electrons moving toward the phosphor-coated faceplate. The electron beam generates a lighted spot where it strikes the phosphor. The intensity of the light is directly related to the density of the electrons hitting a given area of the phosphor. Because this analog operation is not based on any digitizing techniques, most people have little trouble creating a very accurate and simple mental model in their minds of its operation.
Sound and signals in music technology and digital audio
Published in Kirk Ross, Hunt Andy, Digital Sound Processing for Music and Multimedia, 2013
As a first step in understanding the nature of the electrical analogue of sound signals, we might think that some system such as that shown in Figure 2.2 could help us to visualise the construction of sound. An oscilloscope is an electrical instrument which displays variations in voltage (vertical axis) against time (horizontal axis). It therefore traces out fluctuations in voltage over time on its screen. Voltage is a measure of the electrical ‘pressure’ which forces current along the wires of a circuit, and so it is another analogue of sound in our microphone example. The figure shows the waveform which might be observed on an oscilloscope for the words ‘digital audio’ spoken into the microphone.
Electrical measuring instruments and measurements
Published in John Bird, Science and Mathematics for Engineering, 2019
Oscilloscopes are available in both analogue and digital types. An analogue oscilloscope works by directly applying a voltage being measured to an electron beam moving across the oscilloscope screen. The voltage deflects the beam up or down proportionally, tracing the waveform on the screen. This gives an immediate picture of the waveform.
Linear approximation fuzzy model for fault detection in cyber-physical system for supply chain management
Published in Enterprise Information Systems, 2021
The data relation between the theoretical value and the real voltage level value is shown in Table 1. The voltage is fed into the LCD display microprocessor from the distribution box (DB). Only less than 5 v is required for the input into the microprocessor. The microprocessor is burned off due to overvoltage if the voltage is higher than the limit. For stepping the 240 V to 12 V, a step-down transformer is being used. The transformer output is entered into a 5 V output divisor rule (VDR). VDR was known in this venture as the present sensor. The voltage rate output is not always 240 V as a result of the influence of a sinus waveform. The voltage can be between 200 and 240 V depending on the condenser quality used to modify the output voltage on a sinus waveform oscilloscope. For microprocessors, a calculation is needed to set the value to be synchronised on the analogue input with the electric line value are shown in Figure 10.
A PI controller optimized with modified differential evolution algorithm for speed control of BLDC motor
Published in Automatika, 2019
Huang Jigang, Fang Hui, Wang Jie
Experiments are conducted and the results are provided in this section to verify the performance of proposed controller. As Figure 12 shows, the speed control of BLDC motor, which the rated parameters are 3000 rpm, 24 V, 210 W and 0.7 N•M respectively, is implemented based on STM32. The rotor position of BLDC motor is measured by Hall sensor, and the rotor position is then converted into actual speed by derivative algorithm. The output of Hall sensor and the phase voltage waveform are detected by an oscilloscope. A hysteresis brake is connected with BLDC motor by coupling to provide the load for the tests. To prove the validity of the proposed controller, the performances of conventional PI controller and fuzzy PID controller, which is a well-known optimization controller, are taken into consideration as the comparison. The details of fuzzy PID controller are designed from R. Arulmozhiyal's work [37].
Bridge-arm current reduction in DC-AC inverter
Published in International Journal of Electronics, 2018
The 200 V DC-AC single-leg inverter with a load resistor of 100 Ω has been constructed in the laboratory to demonstrate the effectiveness of the proposed. The current spike via the main MOSFET produced by turning on the power device has been measured. The switching frequency is set to 20 kHz. Table 1 shows the main parameter of developed circuit. To clearly display the spike current flowing through the upper and bottom power device, the resistor of 1 Ω is connected in series between the top and bottom bridge arms. The spike current via a single bridge arm with and without the improved circuit of DC voltage at 50 V VDC is shown in Figure 11(a,b), respectively. The load voltage waveform without the improved circuit is connected to oscilloscope and is shown in Figure 11(c). Figure 11(d) shows the voltage waveform across the load in the inverter with the improved coupled inductor. The peak current through the bridge arm is 46 A. During the power device S1 turning-on period, the current spike is clamped at appropriately 2.4 A in the DC-AC inverter with the coupled inductor with diode. The voltage across the main switches is limited to reduce the conduction loss and achieve high efficiency by adding the coupled inductor with diode when low on-state resistor of the power device can be adopted. Comparing case c and d, the load voltage is reduced from approximately 125 to 50 V, which validated the effectiveness of the coupled inductor with diode.