The circuit referenced in this note does have the advantage of using only NPN transistors and no zener. ?However, the I/V curve is less well defined and you have less control over the peak/valley voltages and currents. Otherwise, part count is similar.
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On "my" circuit, since zeners close to 5.5V are almost ideal and have very sharp knees, using one of those puts the peak voltage close to 5.5V; that may be a bit high for many applications. This circuit is very close to piecewise-linear so it is relatively easy to analyze with some precision. ?Some of the behavior DOES depend pretty strongly on the beta of Q1, however; for many transistors, beta can vary over a rather wide range.
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Jim
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On 03/29/2025 10:09 PM PDT alan victor via groups.io <avictor73@...> wrote:
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Along a similar line, this circuit placed in LTspice, provides negative conductance.?
Generate a single DC source sweep on applied V and monitor source current.?
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https://hackaday.com/2019/05/08/fun-with-negative-resistance-jellybean-transistors/#more-356020
