The voltage on the base terminal can be offset to either +2.5V or -2.5V (or 0V) to increase the possible V CE swing (by -2.5 for NPN or +2.5 for PNP). A ratio of 100 for the base and collector resistors is used because beta, the collector current to base current gain, is often approximately 100. The collector current, I C is measured by scope inputs 2+, 2- differentially across a 100Ω resistor. V CE is measured differentially by scope inputs 1+, 1.
#Circuit maker 2000 change probe to current generator
The collector voltage is swept using a ramp from generator W1. In the common emitter configuration, one opamp serves as a virtual ground at the base terminal to convert the voltage steps from waveform generator W2 into base current steps through a 10KΩ resistor. It uses one dual opamp (ADTL082) powered from the +/- 5 Volt board supplies. It will probably be necessary to set the phase of Channel 1 to 90 degrees to make them line up in this way.īelow are schematics for both a common emitter and a common base BJT curve tracer test circuit for use with the ADALM2000. Comparing the waveforms in Channel 1 and Channel 2, the triangle wave in Channel 1 should go through one cycle from 0 to 5 V and back to zero during the time of one step in the waveform in Channel 2. Set the frequency to 200 Hz ( 5 times the 40 Hz of channel 2). In Signal Generator Channel 1 configure a triangle wave with an amplitude of 5V peak-to-peak and an offset of 2.5V (wave should swing from 0 to 5V). For each step to be 5 mSec long for a total of 25 mSec, set the sampling rate 200 Hz. The waveform in the display should start at 0.6V and increase in 1 V increments to 4.6 V (0.6, 1.6, 2.6, 3.6, 4.6). Now at this point set the amplitude to 2 V peak-to-peak and the offset to 2.6 V. Using the Scopy Signal Generator tool, in Channel 2 Buffer tab import the csv file for the stairstep signal needed. The green boxes indicate where to connect the ADALM2000. Build the simple curve tracer circuit shown in Figure 1.
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