Sources pulsed voltage

Vsq - A square wave voltage source. This source uses the pulsed voltage source to make a square wave. It is a special case of Vpulse. 

The length of the simulation is 9 ms. The pulse will start at zero volts and remain there for 3 ms, then go to 5 V for 3 ms, and then return to 0 for another 3 ms. To create this waveform we can use either a pulsed voltage source (VPULSE) or a piecewise linear voltage source (VPWL). For this example we will use the VPWL source. To edit the attributes of the PWL... 

S0LUTI0I1 Use the pulsed voltage source. Set the rise and fall times to 1 ps so that the rise and fall times are much shorter than the pulse width and period of the square wave. Wire the circuit ... 

The pulsed voltage source can be used to create an arbitrary pulse-shaped waveform. We will use it to create a 1 kHz square wave. The rise and fall times of the square wave will be 1 ps. Double-click the LEFT mouse button on the pulsed voltage source graphic, <0, to obtain its spreadsheet and edit its attributes ... 

Click the OK button when you have made the changes to return to the schematic. The input to the inverter will be a short 1 ps pulse. The attributes of the pulsed voltage source are Period = 50u, rise time = In, fall time = In, Pulse width = lu, initial.voltage = 0, Pulsed voltage = 5, delay.time = lu. Double-click the LEFT mouse button on the pulsed voltage source graphic to obtain the spreadsheet for the source ... 

We see that the pulse width is 1 pis and the period is 50 pis long to let the capacitor come into steady state after the pulse. Note that we are simulating the circuit for only one period. We could have used the PWL source, but the pulsed voltage source is easier to set up. Run the simulation and then run Probe. We will first look at the input to see if the pulse is correct Add the trace V (VIN) ... 

The value of the gain is now the value of the parameter FB galn. We would like the input to be a 0 to 5 V step input. The step will be 0 for the first second and then 5 V for the remainder of the simulation. This waveform can be constructed with a pulsed voltage source. Set the attributes of the VPULSE source as shown. On your screen, the attributes will be arranged in alphabetical order. I have changed the order in my screen so that you can see all of the parameters you need to specify ... 

The extraction TOF method can be done using either pulsed or constant voltage sources to the acceleration and repeller grids of a Wiley-McClaren TOF-MS. The first extraction TOF experiments were Mons and Dimicoli [56] on N02 photodissociation using constant voltage sources. Later, Black and Powis [88] used a similar extraction TOF technique, also with constant voltage sources, in order to study CH,I photolysis reactions. Most subsequent experimentalists have used pulsed voltage sources. 

For a six-pulse Voltage Source Inverter (VSI), the inverter output voltage space vector can take any of seven positions in the plane specified by the d-q coordinates. The time integral of the inverter output voltage space vector is called the inverter flux vector for short. The d and q axis components of the inverter flux vector yf, are defined as... 

This is Ihe most commonly used inverter for Ihe control of a.c. motors and is shown in Figure 6.28(a). The fixed d.c. voltage from the uncontrolled rectifier converter acts as a voltage source to the inverter. The voltage in Ihe inverter unit is varied to Ihe required level by using a pulse width modulation, as noted earlier. Through Ihe switching circuit of Ihe inverter Ihe frequency of the... 

Today for this kind of object, the aluminum anodes are usually insulated and connected via cables outside the tank. By this means it is possible to purify and activate the anodes by applying anodic current pulses from an external voltage source. This is necessary during the course of operation since the anode surfaces can be easily passivated by oil films [7]. 

The inverters are either voltage source or current source (see Figure 7-7a and b). There are other variations, but they apply to drivers smaller than the ones used with compressors. However, pulse-width-modulated (PWM) (see Figure 7-7c), transistorized units are less complicated and are relatively maintenance-free with reliable units available to at least 500 hp. For all but the smaller compressors, the current source inverter is the one typically used. With a six-step voltage source, a rule of thumb has been to size the motor at two-thirds of its rating so as not to exceed the insulation temperature rise. For current source motors, the output torque is not constant with decreased speed, which fortunately is compatible with most compressors, as torque tends to follow speed. For current source drives, one needs to upsize the motor captive transformer by approximately 15% to account for harmonic heating effects. 

Figure 7-7. Output from three inverters (A.) Voltage source, (B.) Current source, (C.) Pulse width-modulated source.

RISE TIME - The amount of time the voltage source takes to go from the initial voltage to the pulsed voltage, in seconds. 

CW) (i.e., not pulsed) monitoring source. Note that the voltage signals from photomultipliers are negative. 

The SPICE equivalent circuit schematic is shown in Fig. 4.14. Note that the DCR (DC Resistance) of the inductor LI has been added (R DCR) to the circuit. Also added to the circuit is a voltage source between the inductor and the output in order to measure inductor current. The input voltage is pulsed from V to 20 V in order to help get the simulation started. 

In order to model this in the SPICE programs, the set input was pulsed using an independent voltage source and the following command ... 

In order to fully test the capabilities of this circuit, the input pulse was varied in duty cycle from 5% to 95%. The voltage source VIN used the following two statements ... 

Figure 7.34 Principle of kinetic single-photon counting. L, pulsed light source S, sample P, photodiode F, interference filter or monochromator D, photomultiplier R, voltage ramp generator (1 to start the ramp, 0 to stop it). The voltage V is fed into a multichannel analyser M. Inset voltage ramp V(t)...

The pulses are provided by a precision bipolar voltage source, which is switched into the input of the pulsing amplifier by the switch at point A in the circuit. A very accurate crystal-controlled timing circuit (not shown) drives the switch to ensure that the pulses are symmetrical. The pulsing amplifier inverts the signal as shown by waveform B and supplies current to the cell. The cell current is amplified by the current follower, the output of which is illustrated by waveform C. 

Ion Chambers How can we use this primary ionization to produce a detectable signal The first class of devices to be discussed is the pulse-type ion chambers. A sketch of such a device (a parallel-plate ion chamber) is shown in Figure 18.1. Note that one electrode has been connected to the negative terminal of the voltage source, making it the cathode, while the other electrode acts as the anode. 

As a result of miniaturization several electrical extremes are concentrated on the chip area of ca. 1 cm2 There are DC-voltage-sources in range of -2,000 to 200 V driving electrodes and the MCP, the micro-plasma electron source is powered by a RF-generator at 2.45 GHz, which is ignited by an arc discharge. For the ion separation steep pulse trains of several volts up to 270 MHz with a bandwidth of... 

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