Probe current trace

The marker is now attached to the end of the top pin of the capacitor. Press the ESC key to terminate placing markers. Use the ALT - TAB key sequence to switch back to Probe. The current trace will be displayed ... 

We now have a number of traces displayed. However, the current trace is small. Suppose that we would like to look a little closer at a peak in the current waveform. We can do this by using some of the zoom features provided by Probe. Select View and then Zoom from the menu bar ... 

Instead of deleting a trace, we will display a current trace in a new window. Select Window and then New Window from the Probe menus. A new empty window will open ... 

TOF-SIMS can be applied to identify a variety of molecular fragments, originating from various molecular surface contaminations. It also can be used to determine metal trace concentrations at the surface. The use of an additional high current sputter ion source allows the fast erosion of the sample. By continuously probing the surface composition at the actual crater bottom by the analytical primary ion beam, multi element depth profiles in well defined surface areas can be determined. TOF-SIMS has become an indispensable analytical technique in modem microelectronics, in particular for elemental and molecular surface mapping and for multielement shallow depth profiling. 

As an example of the form of the information that may be derived from a pyrolysis-MS, Figure 26 [69] shows the structure of the polycarbonate (PC) and the EI-MS spectra of pyrolysis compounds obtained by DPMS of poly(bisphenol-A-carbonate) at three different probe temperatures corresponding to the three TIC (total ion current) maxima shown in Figure 27(b) Figure 27 compares the MS-TIC curve with those obtained from thermogravimetry. (The TIC trace is the sum of the relative abundances of all the ions in each mass spectrum plotted against the time (or number of scans) in a data collection sequence [70].)... 

Note that while prototyping, it is a bad idea to insert a current probe (through a loop of wire), anywhere in a critical trace section. The current loop becomes an additional inductance that can increase the amplitude of the noise spikes dramatically. Therefore practically speaking, it can often become virtually impossible to measure the switch current or the diode current individually (especially in the case of switcher ICs). In such cases, only the inductor current waveform can really be measured properly. Sometimes we can place a small sense resistor instead of a current loop, because a good resistor will not create inductive kicks at least. 

We now need to add a trace displaying the diode current. Select Trace and then Add Trace from the Probe menus (or press the INSERT key) and add the trace I(D1) ... 

We have specified a linear sweep from -25°C to 125°C with 1-degree increments. Click the OK button to the schematic. Simulate the circuit and display the results with Probe. Add the trace IC (Q1) to plot the collector current. Use the cursors to label the end points of the range. 

Set up an AC Sweep (PSpice, New Simulation Profile, AC Sweep/Noise) to sweep frequencies from 1 Hz to 1 MHz at 100 points per decade. Run PSpice (PSpice, Run). When Probe runs, add the trace V(l) / I (I test). Remember that voltage divided by current is impedance. We are dividing the voltage between nodes 1 and 0 by the current flowing into and out of those nodes. This is the impedance between those nodes. You will see this trace ... 

Eddy-Current Methods This is one of the earliest NDT methods and is still used Basically, this method reveals any differences tn electrical impedance between parts to be tested and a reference sample. Parts to be examined are passed through a coil or explored with a probe, and a trace appears on a CRT, Since magnetic and electrical characteristics are closely related to metallurgical quantities, a trace position or pattern or a meter reading clearly shows variations in metal hardness and composition, as well as defects. Both ferrous and nonferrous parts can be tested, and various coils, probes, and detector lips are available,... 

The acquisition of data sufficient to prove the structure of a trace level impurity likely remains beyond the routine capabilities of currently available LC/NMR instrumentation and NMR probe technology. 

Surface currents can be followed with the use of ceramic, graphite or quartz floaters this is more difficult with currents in the deeper layers where special submerged probes or isotope tracing are employed. Complete data on the flow rate distribution in a glass tank furnace are difficult to obtain by direct measurement so that... 

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